bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Acute Phase Proteins of Rat Serum. III. Site of Synthesis of Albumin and α1-Acid Glycoprotein and the Contents of These Proteins in Liver Microsome Fractions from Rats Suffering from Induced Inflammation
Authors: Jamieson J. C. , Ashton F. E.
Published: December 2009

Following injection of L-ieucine-3H or D-glucosamine-14C to normal rats or rats suffering from inflammation for 12 h there was a delay of 10–15 min before label appeared in albumin and α1-acid glycoprotein in serum; thereafter, there were rapid increases in specific radioactivities. The specific radioactivity of L-leucine-3H in albumin in serum from normal and experimental animals was not significantly different; however, there was a more rapid increase in specific radioactivities of both labelled compounds in α1-acid glycoprotein isolated from serum from experimental animals. Immunological techniques coupled with radioautography indicated that the microsome fraction of liver was the subcellular site of synthesis of albumin and of carbohydrate and polypeptide moieties of α1-acid glycoprotein in normal and experimental animals. The contents of albumin and α1-acid glycoprotein in liver microsome fractions from normal and experimental animals were determined by application of the quantitative precipitin technique to Lubrol-W extracts of microsome material. Little change in content of albumin associated with microsome material was found as a result of inflammation; however, there was a significant increase in the content of α1-acid glycoprotein in microsome material from experimental animals, reaching a maximum at 8–12 h after inflammation. On the basis of these latter results, it is suggested (1) that there is a fairly rapid stimulation of synthesis of α1-acid glycoprotein by liver in response to inflammation and (2) that the increased content of α1-acid glycoprotein associated with microsome material at short times of exposure to inflammatory agent is responsible for the increased content of this protein found in serum at longer times of exposure to inflammatory agent.
Muscle Creatine: In Vivo Depletion by Feeding β-Guanidinopropionic Acid
Authors: Shields Robert P. , Whitehair C. K.
Published: December 2009

The purpose of this work was to determine the in vivo effect of β-guanidinopropionic acid (β-GPA) on the metabolism of creatine. Diets containing the synthetic creatine analogue, β-GPA, were fed to pregnant female and young male rats.All rats receiving diets containing β-GPA developed the following signs of abnormal creatine metabolism: reduced muscle levels of creatine, reduced urinary excretion of creatinine, and an increase in urinary excretion of creatine.Twelve hours after an injection of creatine-1-14C, rats fed β-GPA had a lower radioactivity level (c.p.m.) in muscle but a higher level in urine than did rats fed the same diet without β-GPA.It is proposed that abnormal creatine metabolism results from an inhibition of creatine entry into muscle from plasma by β-GPA.
Effects of Ionic Strength on the Circular Dichroism Spectrum of Chymotrypsin
Authors: Dorrington K. J. , Hofmann T.
Published: December 2009

The effect of lithium chloride on the circular dichroism spectra of α-chymotrypsin, δ-chymotrypsin, di-isopropylphosphoryl(DIP)-α-chymotrypsin, and chymotrypsinogen at pH 4.0 has been investigated. The spectra showed well-resolved bands at 229, 262, 287, 291, 296, and 305 nm. The 229 band becomes less negative with increasing ionic strength in α- and δ-chymotrypsins, is unaffected in DIP-α-chymotrypsin and chymotrypsinogen, and is probably associated with the changes in reactivity of the N-terminal isoleucine-16. The bands at 262 and 287 nm are affected by lithium chloride in α-chymotrypsin and in DIP-α-chymotrypsin. These changes appear to be associated with dimerization. The 291 band becomes more positive with increasing ionic strength in all three forms of chymotrypsin, but not in the zymogen. The 296 nm band has the same ellipticity in all four proteins and is unaffected by changes in ionic strength. The same applies to the 305 nm band. Evidence is presented which suggests that the changes in the 287 nm transition are due to changes in the environment of tryptophan-215.
Polyacrylaniide Gel Electrophoresis of Rat Liver Mitochondrial Monoamine Oxidases
Authors: Borges J. M. Diaz , D'Iorio A.
Published: December 2009

Solubilized rat liver mitochondria were subjected to polyacrylamide gel electrophoresis. The monoamine oxidase activity was localized directly on the gel with radioactive substrates (serotonin, benzylamine, and tyramine). Serotonin and tyramine monoamine oxidase activity separated in several bands which migrated to the anode and cathode whereas benzylamine activity was localized in one band. This band was demonstrated only when the electrophoresis was run from cathode to anode. Each one of tyramine and serotonin activities could be found devoid of the other two activities. Benzylamine activity could be separated from the serotonin activity though not from the tyramine activity. The detection of monoamine oxidase with the tetrazolium staining provided a localization of the enzyme activity which was different from that observed using radioactive substrates. These results, in accordance with those previously obtained by us with sucrose gradient electrophoresis of the same preparation, support the existence of different enzymes for the oxidative deamination of benzylamine and serotonin. On the other hand our results did not eliminate the possibility of overlapping substrate specificity of tyramine activity with those of serotonin and benzylamine activities.
Influence of pH on the Kinetics of Reactions Catalyzed by Alkaline Phosphatase
Authors: Hinberg Irwin , Laidler Keith J.
Published: December 2009

An experimental study has been made of the kinetics of the hydrolysis of p-nitrophenyl phosphate catalyzed by chicken-intestinal alkaline phosphatase. The work was done in barbital buffer (carbonate above pH 9.6), and covered the pH range from 7.0 to 10.0. A sufficiently wide range of substrate concentration was used to allow reliable values of [Formula: see text] and [Formula: see text] to be determined. The results lead to pK values of 8.1 and 8.6 for the free enzyme, and it is concluded that the Michaelis complex and the phosphoryl intermediate ionize only on the acid side, the former also having a pK of 8.1. It is suggested that the group of pK 8.1 is probably an α-amino group and that the group of pK 8.6 probably corresponds to the ionization of a Zn(II)-coordinated water molecule.
A Novel Procedure for the Purification of Bovine Somatomedin
Authors: Liberti J. P.
Published: December 2009

A procedure for the partial purification of bovine somatomedin (SM) is presented. SM from serum is adsorbed to small pieces of chicken cartilage by exposure of cartilage to serum at room temperature. After 8 h of exposure, the serum is removed and the SM activity adsorbed to the cartilage is recovered by extraction of cartilage with 1.5 M NaCl. The salt extract is centrifuged to remove most of a polysaccharide contaminant and then is dialyzed and concentrated by freeze-drying. Polyacrylamide disc electrophoresis of this material reveals a major zone of SM activity possessing slight anodal migration and a second minor active peak exhibiting marked anodal mobility. The potency of SM so isolated is about 2500-fold more active than native serum and possesses 40–50% of the initial SM activity. The material obtained prior to acrylamide electrophoresis retains about 50% of its activity after 5 months of storage at 6°.It is suggested that this procedure could be of benefit as an initial purification prior to the employment of the classical purification procedures. As this method can be modified readily to accommodate large volumes of serum, it would be possible to isolate milligram quantities of SM for studies in which its chemical and biochemical properties can be elucidated.
Evidence for the Oxidation of N6-(Δ2-Isopentenyl)adenine and N6-(3-Hydroxy-3-methylbutyl)adenine by Xanthine Oxidase
Authors: McLennan B. D. , Pater A.
Published: December 2009

Two known metabolites of N6-(Δ2-isopentenyl)adenosine, namely N6-(Δ2-isopentenyl)adenine and N6-(3-hydroxy-3-methylbutyl)adenine, have been shown to be oxidized by xanthine oxidase. On the basis of ultraviolet absorption and mass spectral data, the oxidation products, in each case, have been tentatively identified as the 8-hydroxy and 2,8-dihydroxy derivatives.
Wheat Embryo Ribonucleates. II. 3′-Hydroxyl Termini of the Satellite, 18 S, and 26 S Ribosomal Ribonucleates
Authors: Azad A. A. , Lane B. G.
Published: December 2009

(1) Terminal labelling with (3H)-borohydride has been used as a means of examining the 3′-hydroxyl termini in wheat embryo RNA.(2) The principal 3′-hydroxyl termini in the "satellite," 18 S, and 26 S components of wheat-embryo ribosomal RNA have been found to be cytidine, guanosine, and uridine, respectively.(3) The occurrence of 3′-hydroxyl terminal cytidine, in satellite RNA, and 3′-hydroxyl terminal guanosine, in 18 S RNA, has never been observed for the corresponding ribosomal ribonucleates from any other source material. The possible significance of this "irregularity" is a subject of discussion.
The Synthesis of Nucleic Acids in Bacillus subtilis Infected with Phage PBS 1
Authors: Rima B. K. , Takahashi I.
Published: December 2009

Unlike other phage systems, the development of PBS 1 was found to be insensitive to rifamycin SV. The incorporation of 3H-uridine into trichloroacetic acid precipitable and alkali-labile material (RNA), in PBS-1-infected cells, was greatly reduced by rifamycin. Observations that RNA synthesized in the presence of rifamycin was hybridizable exclusively with the phage DNA and that actinomycin D inhibited the phage growth indicated that the synthesis of a new species of RNA was required for the development of PBS 1. The host DNA synthesis was reduced to a very low level 5 min after infection. The phage DNA synthesis was also apparently reduced markedly by rifamycin when determined with 3H-uridine as labelling material. On the other hand, rifamycin did not affect the incorporation of 3H-deoxycytidine into the phage DNA, suggesting that phage DNA synthesis was in fact insensitive to rifamycin. It is not clear how rifamycin inhibits the incorporation of 3H-uridine into nucleic acids in PBS-1-infected cells.
Properties of Purified Quinonoid Dihydropterin Reductase
Authors: Cheema Surinder , Soldin S. J. , Knapp Antoinetta , Hofmann T. , Scrimgeour K. G.
Published: December 2009

Quinonoid dihydropterin reductase has been purified to homogeneity from sheep liver, sheep brain, and beef adrenal medulla. Each of these enzymes has a molecular weight of about 45 000–55 000, and is composed of two subunits of half that weight. The subunits of the sheep liver reductase have identical charge, size, and N-terminal amino acid residue. The reductase exists in solution over a wide range of concentrations as the dimer. A dimer covalently linked by dimethylsuberimidate retains full activity. A number of kinetic properties of quinonoid dihydropterin reductase, including inhibition by thiol reagents and by pterin analogues, are reported.
Analysis of 2-Amino-2,6-dideoxyhexoses by Partition Chromatography
Authors: Perry Malcolm B. , Daoust Virginia
Published: December 2009

2-Amino-2,6-dideoxyhexoses can be analyzed by gas–liquid partition chromatography of their 2-acetamido-1,3,4,5-tetra-O-acetyl-2,6-dideoxyhexitol derivatives prepared by borohydride reduction of the parent aminoglycoses followed by acetylation of the resulting aminoglycitols with acetic anhydride in the presence of sodium acetate. Paper chromatographic analysis of the 2-amino-2,6-dideoxyhexoses and their N-acetyl derivatives is also described.
Reaction of Turkey Egg-White Lysozyme with Tetranitromethane. Modification of Tyrosine and Tryptophan
Authors: Riggle Warren L. , Long Jodine A. , Borders Jr. C. L.
Published: December 2009

In a study of the reaction of tetranitromethane with turkey egg-white lysozyme at pH 8.5, it has been found that the number of 3-nitrotyrosine residues formed is dependent on the molar excess of tetranitromethane: 0.6 tyrosines nitrated with a 2.5 M excess; 1.3 with a 25 M excess; and 2.3 with a 250 M excess. Approximately one tyrosine remains unreactive, even with a 250 M excess of tetranitromethane. In each case, the product contains appreciable enzymatic activity: 100% for the 2.5:1 reaction; 48% for the 25:1 reaction; and 40% for the 250:1 reaction. Detectable polymerization of the lysozyme accompanies nitration, as indicated by gel filtration. In addition, the higher ratios of tetranitromethane to lysozyme lead to the modification of tryptophan as well as tyrosine. The most rapidly nitrated tyrosine is tyr-23 in the known sequence of the enzyme.Hydrolysis of the modified lysozymes with 3 N p-toluenesulfonic acid, under conditions normally used to determine the tryptophan content, leads to total destruction of 3-nitrotyrosine.
Plasma Membrane and Nuclear Proteins of the Goose Erythrocyte
Authors: Shelton Keith R.
Published: December 2009

Plasma membrane and nuclear fractions have been prepared from mature goose erythrocytes. Examination of the nonhistone protein of the nuclear fraction by sodium dodecyl sulphate – polyacrylamide gel electrophoresis reveals a limited number of molecular weight species some of which are peculiar to the nuclear fraction.Electrophoretic comparison of the goose plasma membrane proteins with those of the human erythrocyte reveals many similarities. In particular, three large molecular weight species occur in both cells. Their function appears to predate the evolutionary loss of the nucleus.
Recovery of Protease Activities from Complexes with α-Antitrypsin
Authors: Hercz A.
Published: December 2009

For the first time, substantial trypsin and α-chymotrypsin activities were recovered from their α1-antitrypsin-inhibited state. This was achieved by treatment of the α1-antitrypsin–protease complexes with sodium dodecyl sulfate.
Stimulation of Phosphorylcholine–Glyceride Transferase Activity by Unsaturated Fatty Acids
Authors: Sribney Michael , Lyman Eileen M.
Published: December 2009

A number of unsaturated fatty acids markedly stimulate chicken liver microsomal phosphorylcholine–glyceride transferase (CDP-choline:1,2-diglyceride cholinephosphotransferase, EC 2.7.8.2). Oleate (0.8 mM) activates this enzyme severalfold only if a mixed diglyceride such as 1-palmitoyl-2-oleoyl-sn-glycerol is used as a substrate for the reaction. Dipalmitin and diolein incorporation into lecithin is not stimulated to any significant extent by unsaturated fatty acids. Fatty acid esters and numerous detergents either inhibit the enzyme or have no effect. Phosphorylethanolamine–glyceride transferase (CDP-ethanolamine:1,2-diglyceride ethanolaminephosphotransferase, EC 2.7.8.1) activity is only very slightly stimulated while diglyceride O-acyltransferase activity is inhibited to a small extent.
Fatty Acid Profile of Plasma Lipid Classes in Coronary Heart Disease, in Primary Hyperlipoproteinemias, and in Healthy Subjects
Authors: Allard Claude , Davignon Jean , Marcel Yves L. , Goulet Claude , Kuba Kanta , Alteresco Monica , Caradec Yves , Plante Denise
Published: December 2009

The plasma fatty acid composition of the cholesteryl esters triglycerides, and total phospholipid was studied by gas–liquid chromatography in clinically healthy subjects and coronary patients; all of whom had had a recent selective coronary arteriography. The fatty acid composition of the same lipid classes mentioned above was investigated in the different types of hyperlipoproteinemia. All the subjects or patients investigated were on a regular diet. The fatty acid patterns in the various lipid classes were found the same in coronary patients and in healthy subjects. However, great differences were noted in the fatty acid profiles in the various types of hyperlipoproteinemia. Noteworthy was the fact that type II (especially type IIa) contained the greatest proportion of linoleic acid in all lipid classes. This study indicated again biochemical heterogeneity within types of primary hyperlipoproteinemias and also between types IIa and IIb.
Stability of Cytoplasmic Messenger RNA in Stationary and Exponentially Growing Rabbit Lung Cells
Authors: Schultz Gilbert A.
Published: December 2009

The metabolic stability of polysomal poly (A)-containing messenger RNA in exponentially growing and stationary cultures of rabbit lung cells has been estimated under conditions that do not involve the use of inhibitors of RNA synthesis. The method employed measures the spectrum of stability of messenger RNA by the analysis of the kinetics of incorporation of radioactive uridine into uridine triphosphate and into polysomal poly (A)-containing messenger RNA. The polysomal poly (A)-containing messenger RNA in exponentially growing cells with a generation time of 18 h has an apparent uniform half-life of about 18 h compared to an average half-life of 24 h in stationary cells.
The Mechanism of Replication of Single-Stranded DNA. VI. Requirements for Ribonucleoside Triphosphates and DNA Polymerase III
Authors: Denhardt David T. , Iwaya Makoto , McFadden Grant , Schochetman Gerald
Published: December 2009

Evidence is presented that in Escherichia coli made permeable to nucleotides by exposure to toluene, the synthesis of a DNA chain complementary to the infecting single-stranded DNA of bacteriophage [Formula: see text] requires ATP as well as the four deoxyribonucleoside triphosphates. This synthesis results in the formation of the parental double-stranded replicative-form (RF) molecule. The ATP is not required simply to prevent degradation of the ribonucleoside or deoxyribonucleoside triphosphates; it can be partially substituted for by other ribonucleoside triphosphates.No single one of the known E. coli DNA polymerases appears to be uniquely responsible in vivo for the formation of the parental RF. Since [Formula: see text] replicates well in strains lacking all, or almost all, of the in-vitro activities of DNA polymerases I and II, neither of these two enzymes would seem essential; and in a temperature-sensitive E. coli mutant (dnaEts) deficient in DNA polmerase-I activity and possessing a temperature-sensitive DNA polymerase III, the viral single-stranded DNA is efficiently incorporated into an RF molecule at the restrictive temperature. In contrast, both RF replication and progeny single-stranded DNA synthesis are dependent upon DNA polymerase III activity.
Crambe Thioglucoside Glucohydrolase (EC 3.2.3.1): Separation of a Protein Required for Epithiobutane Formation
Authors: Tookey H. L.
Published: December 2009

Sonicated extract of crambe seed meal prepared in the presence of ferrous ion and dithiothreitol enzymatically converts epi-progoitrin to glucose, HSO4−, and a mixture of 1-cyano-2-hydroxy-3,4-epithiobutanes (50–70%) and 1-cyano-2-hydroxy-3-butene (30–50%). A fraction of the extract precipitating between 60 and 70% saturated ammonium sulfate contains thioglucosidase that converts epi-progoitrin essentially to 1-cyano-2-hydroxy-3-butene. Chromatography (on cross-linked dextran) of a 40–60% ammonium sulfate fraction leads to separation of a proteinaceous material (s20 = 2.6 S) that does not hydrolyze epi-progoitrin but, in the presence of thioglucosidase, promotes the formation of 1-cyano-2-hydroxy-3,4-epithiobutanes in amounts proportional to those from crude seed meal extract.
Correction to the Amino Acid Sequence of Porcine Motilin
Authors: Schubert Harold , Brown John C.
Published: December 2009

A comparison of the electrophoretic mobilities of the tryptic peptides of natural porcine motilin and a synthetic analogue with norleucine substituted for methionine revealed the absence of the acidic peptide TR3 of the natural material. Kinetic studies with leucine aminopeptidase and dansyl-Edman degradations on this peptide revealed the presence of glutamine at position 14 and not glutamic acid as previously reported. It is suggested that in the earlier preparation of natural porcine motilin deamidation of glutamine occurred.
Direct Conversion of 17β-Estradiol-3-ghicosiduronate and 17β-Estradiol-3-sulfate to their 17-Keto Forms by Human Kidney Homogenates
Authors: Hobkirk R. , Green R. N. , Nilsen M. , Jennings B. A.
Published: December 2009

Labelled 17β-estradiol-3-glucosiduronate and 17β-estradiol-3-sulfate were both directly dehydrogenated to their respective 17-keto forms on incubation with human kidney homogenates. NAD increased the conversion to a greater extent than did NADP. The reverse reaction, even in the presence of NADH or NADPH was not found to a measurable extent, presumably because of rapid oxidation of the cofactors. High or low activity towards the conjugates was accompanied by high or low activity, respectively, towards free 17β-estradiol. These dehydrogenase activities were particularly high in the medulla of one kidney so investigated. Considerable sulfatase activity was usually encountered in these homogenates but little β-glucuronidase activity was demonstrated under the experimental conditions.
Properties of P503 (Prototetrahydroporphyrin IX) in Cells and Extracts of Saccharomyces cerevisiae
Authors: Poulson Rozanne , Boon Joyce , Polglase W. James
Published: December 2009

Both ρ+ and ρ− strains of Saccharomyces cerevisiae accumulate P503 during the early logarithmic phase of growth when cytochrome synthesis is repressed. Yeast cells grown on non-fermentable carbon sources (e.g. glycerol) did not accumulate P503. Cell-free extracts containing P503 were prepared from anaerobically grown (ρ+) S. cerevisiae. The addition to these extracts of mitochondria from ρ+ cells grown aerobically on galactose caused the immediate disappearance of P503. Escherichia coli respiratory particles had a similar effect on P503. Mitochondrial preparations from ρ− cells or from anaerobically grown ρ+ cells did not affect P503. Coprotetrahydroporphyrin III was not oxidized by aerobic S. cerevisiae mitochondria nor by E. coli respiratory particles.
Biosynthesis of Branched-Chain Amino Acids in Schizosaccharomyces pombe: Regulation of the Enzymes Involved in Isoleucine, Valine, and Leucine Synthesis
Authors: McDonald Roderick A. , Satyanarayana T. , Kaplan J. G.
Published: December 2009

The activities and regulation of the enzymes of the synthetic pathway of branched-chain amino acids were investigated in the fission yeast, Schizosaccharomyces pombe. Previous studies had shown the presence of threonine deaminase (TD) and acetohydroxy acid synthetase (AHAS). The remaining isoleucine–valine enzymes, isomeroreductase (IR), dehydrase, and transaminase B, have now been characterized in cell-free extracts, indicating the presence in this yeast of the complete pathway as demonstrated in other microorganisms. α-Isopropylmalate synthetase (IPMS), the first enzyme of the leucine pathway, has properties of a typical regulatory enzyme; it is most active in the pH range 7.5–8.5, but is most sensitive to feedback inhibition by L-leucine at pH 6.5–7.0. Unlike the situation in baker's yeast, only AHAS and IR appeared to be subject to multivalent repression. TD was relatively resistant to any change in level, and AHAS was repressible by valine included in the growth medium. IPMS was repressed when cells were grown in complex medium; leucine alone did not cause repression, and in contrast with baker's yeast, neither did leucine plus threonine or a combination of all three branched-chain amino acids.
Metabolism and Transport of Purine Nucleosides by Membrane Preparations of Micrococcus sodonensis
Authors: Pickard M. A. , Phillippe Lucille , Campbell J. N.
Published: December 2009

The uptake and metabolism of adenosine-8-14C was studied using isolated membrane vesicles prepared from Micrococcus sodonensis. When the adenosine concentration was 1.0 mM, a concentration that caused prolonged bacteriostasis in growing cells, the membranes vesicles initially accumulated adenosine and inosine to similar levels but rapidly became enriched with inosine. However, when the external adenosine concentration was lowered to 0.1 mM, the vesicle contents were almost entirely inosine. No compounds other than adenosine and inosine were detected. These effects were shown to be the result of a membrane-bound adenosine deaminase and are in marked contrast to the phosphoribosyltransferase-linked mechanisms of purine nucleoside transport in other bacterial systems.
Adenosine-3′,5′-Monophosphate-Dependent Protein Kinase From Bovine Anterior Pituitary Gland. III. Structural Specificity of the ATP Site of the Catalytic Subunit
Authors: Lemaire Simon , Labrie Fernand , Gauthier Marie
Published: December 2009

The effect of analogues and derivatives of adenosine 3′,5′-monophosphate (cyclic AMP) and of ATP on the incorporation of 32P from [γ-32P]ATP into histones has been measured using the purified catalytic subunit of adenohypophyseal protein kinase. Gamma-labeled CTP, GTP, and UTP cannot substitute for [γ-32P]ATP but they slightly inhibit the phosphorylation by [γ-32P]-ATP when present as unlabeled compounds. A stringent requirement of the adenine nucleus is observed for the ability to compete at the ATP site, inhibitions of 42, 39, 32, and 63% being observed respectively with adenine, adenosine, 5′AMP, and ADP, while the corresponding purine or pyrimidine derivatives have no effect when present at a 13-fold molar excess relative to [γ-32P]ATP. The N6-benzoyl and N6-butyryl derivatives of cyclic AMP are inactive whereas the 8-substituted derivatives are generally as active as cyclic AMP itself, except for the 8-amino- and 8-hydroxy-derivatives, which exhibit a lower degree of competition. All cyclic AMP and ATP analogues and derivatives that inhibit histone phosphorylation by [γ-32P]ATP act as competitive inhibitors. Such competition at the ATP site of the catalytic subunit of protein kinase probably accounts for the progressive inhibition of cyclic-AMP-dependent protein kinase activity measured at high concentrations (above 10−5 M) of the cyclic nucleotide.
Development of Hydroxytryptophan Decarboxylase Activity in the Pineal Gland, Cerebral Hemispheres, and Cerebellum of the Chick Embryo and Young Chick
Authors: Wainwright S. D.
Published: December 2009

The courses of increase in 5-hydroxytryptophan decarboxylase activity in the chick pineal gland, cerebral hemispheres, and cerebellum have been followed from the 10-day embryo to 2-weeks post-hatch. Activity was first detected in the pineal gland and cerebral hemispheres of 12-day embryos, and in the cerebellum of 18-day embryos. In each tissue, there was a rapid initial rise in activity to about the stage of hatching, followed by a further less rapid rise to levels of 50–100% of those found for adult birds.
Studies on Acid Hydrolases in Embryonic Rabbit Brain: Prenatal Ontogeny of Cerebral Glycosidases
Authors: Clarke J. T. R.
Published: December 2009

With the use of artificial substrates, the ontogeny of α-galactosidase, β-galactosidase, N-acetyl-β-glucosaminidase, N-acetyl-β-galactosaminidase, β-glucuronidase, α-fucosidase, α-mannosidase, arylsulfatase, and acid phosphatase activities was studied in embryonic rabbit brain from 12 days gestational age to birth. There was significant activity of all the hydrolases in the rabbit brain from an early stage of development. There was little correlation between the activities of the various acid hydrolases in individual litters, but some common patterns of development became apparent. The subcellular distribution of glycosidase activities in the brains of 20- and 24-day embryos were identical and compatible with localization in lysosomes. Glycosidase activity in other subcellular organelles, e.g. plasma membrane, could not be ruled out however.
Metabolism of Acid-Soluble Nucleotides in Starved–Refed-Synchronized Tetrahymena pyriformis GL
Authors: Stocco D. M. , Zimmerman A. M.
Published: December 2009

The metabolism of acid-soluble and acid-insoluble material was investigated in starvation–refed synchronized Tetrahymena pyriformis. RNA synthesis was initiated 90 min after the addition of enriched nutrient medium, whereas DNA synthesis was not detectable until 180 min after refeeding. Studies on the acid-soluble pool indicated that the incorporation of radioactive precursors into the soluble nucleotide pool increased with time following refeeding of the cells; the increased incorporation of radioactive precursors in the acid-soluble nucleotide pool parallels the increase in nucleic acid synthesis.Further investigations indicated that starvation-synchronized cells were able to convert almost 80% of adenine ribonucleotide to adenine deoxyribonucleotide in a 30 min period during DNA synthesis. This conversion apparently served as an additional source of precursors for the synchronous burst of DNA synthesis observed in these cells. In contrast logarithmic cells and heat-synchronized cells converted less than 10% of this ribonucleotide to the deoxyribonucleotide during a 30 min period.
Two cAMP-Activated Protein Kinases from Bovine Thyroid
Authors: Wilson M. Barbara , Malkin Aaron
Published: December 2009

Two cAMP-activated protein kinases (ATP:protein phosphotransferase, EC 2.7.1.37) were purified from bovine thyroid tissue by column chromatography on Sephadex G-200 and DEAE-Sephadex A-25. Maximal stimulation by cAMP of enzyme I was 1.7-fold and of enzyme II was 3.7-fold. The total (basal plus cAMP-activated) specific activities of the purified enzymes I and II were, respectively: 3190 and 6430 protein kinase units (picomoles phosphate transferred per milligram protein per 10 min).The properties of the thyroid protein kinases were found to be similar to those of protein kinases isolated from other tissues. For enzyme I, Km(cAMP) was 20 × 10−8 M, Km(cGMP) was 416 × 10−8 M, and Km(ATP) was 0.02 mM. For enzyme II, Km(cAMP) was 6 × 10−8 M, Km(cGMP) was 250 × 10−8 M, and Km(ATP) was 0.03 mM. For both enzymes, Km(histone) was 1.33 mg/ml, Km(Mg2+) was 2.6 mM, and the pH optimum lay between pH 6.0 and pH 6.5. The cAMP had no effect on the Km values of either I or II for histone, ATP, or Mg2+. The subcellular distribution study indicated that 80% of the total kinase activity was present in the 100 000 × g supernatant fraction.
Nuclear Proteins during Development: Incorporation of Leucine into Histones of Rainbow Trout during Early Development
Authors: Trevithick J. R.
Published: December 2009

Nuclear histones of embryos of rainbow trout (Salmo gairdnerii) were isolated after incubation of cell suspensions with [4,5-3H]leucine. The incorporation of leucine into nuclei at 10 °C was found to occur linearly for 4 h. At all stages examined from very early blastula to [Formula: see text] epiboly, a component identical in mobility to histone I was found when a sensitive staining technique was employed. The relative proportion of histone IIId is higher at early blastula, and decreased by mid-blastula to a level which remains constant relative to other components during the remainder of the stages examined. The major proportion of the leucine incorporated into histones is found at all stages in histones IIb1 and IIb2, but as development occurs, the relative proportion of incorporation into histone IV increases until at [Formula: see text] epiboly, it is almost equal to either histone IIb1 or IIb2.
Patterns of Incorporation of [32P]orthophosphate and [3H]acetate into Histones of Rainbow Trout during Early Development
Authors: Trevithick J. R.
Published: December 2009

Nuclear histones of embryos of rainbow trout (Salmo gairdnerii) were isolated after incubation of cell suspension with [32P]orthophosphate and sodium [3H]acetate. In all stages examined from early blastula to neurula, the major proportion of phosphate incorporated was located in histones IIb1 and I. The major histones into which acetate was incorporated were IIb2 and/or IIIm and I. Peaks of acetate and phosphate do not appear at the same positions on acrylamide gels of doubly labelled histones and thus acetylation and phosphorylation appear to be two different alternative or sequential processes. Tryptic digestion of IIb1 indicates that the main site of phosphate incorporation into IIb1 is similar to that found in trout testis, but it is possible that a difference exists since, after thermolysin digestion, the phosphopeptides obtained are not identical with those reported for trout testis IIb1.
Urinary Excretion of Cyclic AMP by Cold-Acclimated Rats
Authors: Muirhead Michelle , Inglis Aileen , Himms-Hagen Jean
Published: December 2009

Cold-acclimated rats living in the cold (4°) excrete more cyclic AMP in their urine than do control warm-acclimated rats living at room temperature (26°–28°). However, cold-acclimated rats, returned to the cold after a few days at room temperature and presumably raising their metabolic rate by nonshivering thermogenesis in response to the noradrenaline and adrenaline secreted by the sympathetic nervous system, excrete the same amount of cyclic AMP in their urine as do warm-acclimated rats of the same age put into the cold for the first time and presumably raising their metabolic rate by shivering. Thus, no evidence could be found for an altered utilization of the adenyl cyclase system in the cold-acclimated rat. This, together with previous findings of unaltered levels and properties of noradrenaline-stimulated adenyl cyclase in brown adipose tissue and skeletal muscle of cold-acclimated rats, leads us to the conclusion that the enhancement of the metabolic response to noradrenaline in cold-acclimated rats is not due to any alteration in the adenyl cyclase system.
Purification de la Chymotrypsine A de Porc, par Elution Sélective en Chromatographie d'Affinité
Authors: Bergeron Louise , Médicis Eveline de
Published: December 2009

Hog chymotrypsin A was purified from an acid extract of pancreas and subjected to chromatography on Sepharose–caproyl, D-tryptophan methyl ester, and Sepharose-4-phenylbutylamine. It was demonstrated that the adsorption of chymotrypsin on those ligands was nonspecific and that it was necessary to apply a gradient of ionic strength and pH to separate the adsorbed species. It was concluded that the so-called affinity chromatography does not differ from classical adsorption chromatography if the ligand interacts with a dissociation constant around millimolar.
Isolation from Rabbit Urine of the 3-Glucuronide-17-N-acetylglucosaminide of 17α-Estradiol
Authors: Gwilliam Cynthia , Paquet Alenka , Williamson Denis G. , Layne Donald S.
Published: December 2009

Large amounts of 6,7-[3H]estrone benzoate were injected into female rabbits, and the double glycoside of 17α-estradiol, which is excreted in the urine after such treatment, was isolated in crystalline form for the first time. The material was converted to its peracetylated 3-methyl ester, the infrared and nuclear magnetic resonance spectra of which, as well as the elemental analysis, supported previous evidence that the excreted conjugate was 17α-estradiol-3-β-D-glucuronide-17-β-D-N-acetylglucosaminide. The chromatographic patterns on Sephadex A-25 confirmed that this compound is quantitatively by far the major metabolite of injected estrone in the rabbit.
Biosynthesis of Nitrogenous Phospholipids in Spinach Leaves
Authors: Marshall M. O. , Kates M.
Published: December 2009

Pathways for biosynthesis of phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylcholine (PC), in spinach leaves have been studied both in vivo (whole leaves and leaf slices) and in vitro (cell-free leaf fractions). Biosynthesis of PS was shown to occur by the action of a particle-bound CDP-diglyceride: serine phosphatidyltransferase, and PE by the action of a PS-decarboxylase localized in the 100 000 × g supernatant fraction. PE was also formed by the operation of the CDP-ethanolamine:diglyceride phosphorylethanolamine transferase, localized in the microsomal fraction. The presence of ethanolamine kinase required for formation of phosphorylethanolamine was demonstrated in vitro, but not the presence of CTP:phosphorylethanolamine cytidyltransferase; however, the latter is presumed present on the basis of in vivo results. Operation of the methylation pathway for biosynthesis of PC was established in vivo, and direct methylation of phosphatidyl-N-methylethanolamine to phosphatidyl-N,N-dimethylethanolamine (PE-diMe) and of PE-diME to PC by S-adenosylmethionine was demonstrated with a particulate enzyme system localized in the microsomal fraction; direct methylation of PE itself could not be shown in this system. PC was also synthesized by the CDP-choline:diglyceride phosphorylcholine transferase system localized in the microsomal fraction. Synthesis of PE and PC by Ca2+-stimulated exchange reactions with ethanolamine and choline, respectively, could be demonstrated, but at low rates. However, no synthesis of PS by exchange reactions with serine could be detected.
Preparation and Properties of Purified (Na+ + K+)-Stimulated Mitochondrial ATPase from Germinating Pea Seeds
Authors: Malhotra S. S. , Spencer Mary
Published: December 2009

An ATPase preparation from pea cotyledon mitochondria was purified by protamine sulfate, ammonium sulfate precipitations, and preparative gel electrophoresis. The ATPase activity was dependent upon Mg2+ and stimulated by Na+ + K+. The optimum pH of the enzyme was 8.0. A ratio of 5 to 1 between Na+ and K+ must be maintained to show maximum ATPase activity. Although no detectable amounts of phospholipids were found to be associated with the purified enzyme, it was activated by Na+ and K+ ions. Addition of phosphatidylserme and phosphatidylinositol resulted in increased activity of the (Na+ + K+)-stimulated enzyme, suggesting that the purified enzyme has probably lost most of the membrane complement during purification.
Protein Kinases in Testes of Adult and Prepuberal Rats
Authors: Bernard E. A. , Wassermann G. F.
Published: December 2009

Cyclic AMP dependence of protein kinase activity (PrK) in testicular homogenates varies according to the substrate used (histone > casein). The enzymatic activity increased during maturation, notably between 35 and 45 days of age. The increment is higher in isolated seminiferous tubules than in interstitial tissue. Upon centrifugation at pH 4.8, two dissimilar PrK preparations can be obtained. The enzymatic activity of both fractions increased with maturation.
Phosphonolipids. XXVI. Mixed-Acid Phosphonocephalins: Synthesis of α′-Stearoyl- β-oleoyl-L-α-glyceryl-(2-aminoethyl)phosphonate
Authors: Baer Erich
Published: December 2009

The synthesis of α′-stearoyl-β-oleoyl-L-α-glyceryl-(2-aminoethyl)phosphonate is reported. It is a member of a new class of phosphonolipids containing two dissimilar fatty acid substituents, one of which is unsaturated and occupies the 2 or β position of the glycerol moiety. The mixed-acid phosphonolipid, a phosphonic acid analogue of naturally occurring L-(α-stearoyl-β-oleoyl)cephalin, was obtained by phosphonylating D-α-stearoyl-β-oleoylglycerol with (2-phthalimidoethyl) phosphonic acid monochloride and triethylamine, and freeing the resulting α-stearoyl-β-oleoyl-L-α-glyceryl-(2-phthalirnidoethyl)phosphonate of its protective phthaloyl group by hydrazinolysis.
Electrophoretic Analysis of Polypeptides of Plasma Membranes from Bovine Pituitary Gland
Authors: Lemay André , Labrie Fernand
Published: December 2009

Purified plasma membranes from bovine hypophyseal tissue have been fractionated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis under various conditions of pH and acrylamide concentrations. The best separation of protein components is achieved at a concentration of 7.5% acrylamide and at pH 7.1. Under these conditions, the electrophoretic pattern consistently shows 36 protein bands ranging in molecular weights from 250 000 to 15 000. Only one broad band, having an apparent molecular weight of 150 000, stains for glycoproteins by the period acid – Schiff technique. After electrophoresis on a two-dimensional polyacrylamide gel system using disc gels containing urea and Triton X-100 in the first dimension and SDS in the second dimension, approximately 45 different protein components can be identified. Less than 12% of the membrane proteins are solubilized by washing the membranes with 1 M KCl or NH4Cl. Denaturating agents like urea and lithium 3,4-diiodosalycilate solubilize 55–60% of membrane components. Adenohypophyseal plasma membranes show an eleetrophoretic pattern completely different from that obtained with membranes isolated from the intermediate or posterior pituitary lobes.
Intermolecular Steric Interactions and Lipid Chain Fluidity in Phospholipid Multibilayers. A Spin Label Study
Authors: Marsh D.
Published: December 2009

The temperature variation of the spectra of stearic acid spin labels has been investigated in oriented egg lecithin multibilayers. The temperature behavior is characterized by an effective value for the energy separation between trans and gauche conformations in the lipid chains. Comparison with bilayers containing cholesterol indicates that this effective energy is sensitive to intermolecular steric interactions. The large value for the effective gauche energy suggests that part of the lipid chains are in a relatively ordered state even in unsaturated lecithin systems.
Estimation of the Water of Hydration in Wintering Wheat Leaves by Proton Magnetic Resonance
Authors: Macdowall F. D. H. , Buchanan G. W.
Published: December 2009

Water of hydration in whole tissues of wheat leaf sheaths was estimated by Kuntz' proton magnetic resonance method as the fraction of water that was withheld by macromolecular restraint from ice formation. The tissues bound up to 0.5 g water per gram dry weight. At −25 °C, which killed all tissues, the proton signals of unfrozen water were of greater magnitude from tissues and press sap of more hardy (frost resistant) plant material.
Incorporation of Sialic Acid into Sialidase-Treated Apolipoprotein of Human, Very Low Density Lipoprotein by a Pork Liver Sialyltransferase
Authors: Wetmore Stephen , Mahley Robert W. , Brown W. Virgil , Schachter Harry
Published: December 2009

Pork liver microsomes are capable of catalyzing the incorporation of N-14C-acetylneuraminic acid from CMP-N-14C-acetylneuraminic acid into a sialidase-treated apolipoprotein (apoLP-Ala1) prepared from human, very low density lipoprotein and into sialidase-treated ovine submaxillary mucin. The pH optimum for the lipoprotein sialyltransferase is 5.8, and the Km values for CMP-N-acetylneuraminic acid, sialidase-treated apoLP-Ala1 and sialidase-treated ovine submaxillary mucin are, respectively, 0.04 mM, 0.04 mM, and 10 mM. Mixed substrate experiments indicate that the same sialyltransferase acts on both lipoprotein and mucin acceptors but that this enzyme is different from a previously described pork liver sialyltransferase which incorporates N-acetylneuraminic acid into linkage with the terminal galactose residues of sialidase-treated α1-acid glycoprotein. The radioactive product of the lipoprotein sialyltransferase releases, on treatment with alkaline borohydride, a reduced oligosaccharide tentatively identified as N-14C-acetylneuraminyl-N-acetylgalactosaminitol.
Phosphonolipids. XXVII. Synthesis of O-(2-Aminoethyl)phosphono-L-serine and its Stereoisomer
Authors: Baer Erich , Eber Jeno T.
Published: December 2009

The synthesis of O-(2-aminoethyl)phosphono-L-serine and O-(2-aminoethyl)phosphono-D-serine is described. The phosphonic acid analogues were obtained by the reaction of O-(2-N,N-dibenzylaminoethyl)phosphonic acid monochloride and triethylamine with N-carbobenzoxy-L-serine benzyl ester and N-carbobenzoxy-D-serine benzyl ester, respectively, followed by the simultaneous removal of the protective carbobenzoxy- and benzyl groups of the reaction products, i.e. O-(2-N,N-dibenzylaminoethyl)phosphono-N-carbobenzoxy-L-serine benzyl ester and its stereoisomer, by hydrogenolysis in 95% ethanol with palladium black catalyst in the presence of sulfuric acid. The O-(2-aminoethyl)phosphono-L-serine and its stereoisomer were obtained in overall yields of about 40% of theory. They are phosphonic acid analogues of the naturally occurring O-(ethanolamine)-O-(L-serine)phosphate diester and its stereoisomer, respectively.
Isolation of Dimethylallylpyrophosphate:Umbelliferone Dimethylallyltransferase from Ruta graveolens
Authors: Ellis B. E. , Brown Stewart A.
Published: December 2009

The enzyme catalyzing the first reaction specifically directed to furanocoumarin synthesis has been isolated from suspension cultures and young leaves of Ruta graveolens. With umbelliferone, Mn2+, and dimethylallylpyrophosphate as substrates the enzyme converts umbelliferone to 6-dimethylallylumbelliferone (demethylsuberosin), an established intermediate in the biosynthesis of linear furanocoumarins, but not to 8-dimethylallylumbelliferone (osthenol), the analogous intermediate in angular furanocoumarin biosynthesis. Herniarin does not substitute for umbelliferone, nor geranylpyrophosphate for dimethylallylpyrophosphate. The enzyme activity is associated with particles that sediment readily at high centrifugal force.
Steroid Metabolism by the Immature Rat Testis
Authors: Moger W. H. , Armstrong D. T.
Published: December 2009

Treatment of hypophysectomized immature male rats with luteinizing hormone (LH) greatly increased the metabolism of both 4-[14C]progesterone and 4-[14C]testosterone by testicular homogenates. Prolactin, either alone or in combination with LH, did not influence the metabolism of either substrate. Progesterone was metabolized to 17α-hydroxyprogesterone, androstenedione, 5α-pregnan-3,20-dione, 3α-hydroxy-5α-pregnan-20-one, and 3β-hydroxy-5α-pregnan-20-one. Testosterone was metabolized to dihydrotestosterone and 5α-androstan-3α,17β-diol. On the basis of these observations it is suggested that LH stimulated the 5α-reductase(s) of the immature rat testis. Testis homogenates from immature rats with intact pituitaries were incubated with 4-[14C]3α-hydroxy-5α-pregnan-20-one. Rapid conversion to androsterone was observed, with the formation of a compound chromatographically identical with 3α, 17α-dihydroxy-5α-pregnan-20-one as an apparent intermediate. These findings demonstrate the ability of the rat testes to form androsterone from progesterone by a pathway that does not involve testosterone.
Structural Studies of Bacteriorhodopsin from Halobacterium cutirubrum by Resonance Raman Spectroscopy
Authors: Mendelsohn R. , Verma A. L. , Bernstein H. J. , Kates M.
Published: December 2009

Resonance Raman spectra are reported for suspensions of the membrane-bound protein "bacteriorhodopsin" isolated from Halobacterium cutirubrum. Most of the observed vibrations arise from the conjugated Schiff base of retinal in the chromophore. Excitation profiles for two C=C stretching vibrations at 1529 cm−1 and 1568 cm−1 show that the former is coupled to the 560 nm pigment absorption band, whereas the latter is coupled to a shorter wavelength transition. The 1529 cm−1 mode is shifted by ~40 cm−1 from retinylidenelysine in solution showing that the π electron system of the Schiff base is considerably perturbed by the protein. It is this interaction that is responsible for the bathochromic shift in the pigment.The addition of diethyl ether shifts λmax to 460–490 nm, and causes a decrease in the intensity at 1529 cm−1, with a concomitant increase at 1568 cm−1. The effect is reversible. Ether appears to weaken considerably the chromophore–protein interaction, making the chromophore more vulnerable to chemical reagents.