Abstract:
The present invention relates to novel key intermediates for the production of biologically active compounds coupled to polymers, of the general formula P--NCX 2 , wherein X designates a halogen atom selected from chlorine and bromine, and wherein P designates the polymer backbone of a polymer of the polyamide, polyester and ureaformaldehyde type. The invention further relates to compounds obtained by the reaction of the above compound P--NCX 2  with a bifunctional or polyfunctional nucleophile. Suitable nucleophiles are hydrazides of dicarboxylic acids and amongst these there may be mentioned polyacrylamides partially substituted with acylhydrazide groups; polyfunctional amines selected from alkylamines, aralkylamines, arylamines and macromolecular compounds containing amino groups. The key intermediate PNCX 2  may be coupled directly to biologically active macromolecules and amongst the preferred compounds of this type there are the various biologically active proteins and enzymes. The coupling of the biologically active macromolecules may also be effected via hydrophilic polymer moieties first grafted onto the polymer P via said dihaloisocyanide groups.

Description:
FIELD OF THE INVENTION 
     The present invention relates to novel dihaloisocyanide derivatives of polymers and to products obtained by coupling to these key intermediates various nucleophiles. The preferred new compounds are dihaloisocyanide derivative of polymers selected from various types of polyamides, polyesters and urea-formaldehyde polymers wherein halo designates chlorine or bromine. When such dihaloisocyanide polymers are coupled with nucleophiles there are obtained various valuable products. The dihaloisocyanides can be coupled with biologically active macromolecules such as proteins, and the biological activity of these is retained to a large degree. The dihaloisocyanide polymers can be first reacted with a polymer containing nucleophilic groups capable of undergoing reaction with the dihaloisocyanide groups and the resulting product can be used for coupling biologically active macromolecules. Amongst preferred polymers coupled to the dihaloisocyanide polymers there may be mentioned hydrophilic polymers, and when the product is coupled with biologically active macromolecules the stability of the biologically active product is enhanced. The invention further relates to a process for the production of the various above defined novel products and more specifically to the production of the dihaloisocyanide substituted polymers and to the production of the various products obtainable therefrom by reaction with suitable nucleophiles. 
     BACKGROUND OF THE INVENTION 
     There is known a method for the direct covalent bonding of biologically active molecules to chemically modified polyamides, such as various types of nylon (nylon 6, nylon 66). The known method involves a 4 -component condensation reaction of an amine, a carboxyl moiety, an aldehyde, and an isocyanide: generally the polymeric carrier provides the isocyanide moieties, and the protein the amine or the carboxyl moieties, an aldehyde and the forth component being added to the reaction mixture. It is one of the drawbacks of this known method that the biological activity of certain compounds is impaired by the aldehyde. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a novel type of modified polymeric carriers which are very reactive and which are utilized for the covalent bonding of biologically active proteins. The novel polymeric carriers are strongly electrophilic dihaloisocyanide derivatives. The preferred dihaloisocyanides are dibromoisocyanides, the second choice being dichloroisocyanide derivatives. The invention is illustrated mainly with reference to the dibromo derivatives, but the corresponding dichloro derivatives can also be used. 
     In the most general terms P designates a suitable polymeric backbone, and the starting material is thus a derivative thereof with --N═C functional groups, which is converted to ##STR1## derivatives or to ##STR2## derivatives which can be reacted with various compounds having at least one nucleophilic group, resulting in the coupling of such compounds to the polymeric backbone. Amongst nucleophiles which can be used there may be mentioned various bifunctional or polyfunctional amines, such as alkylamines, arylamines, aralkylamines and macromolecular compounds containing amine groups. The polymer can be modified by reacting it with another polymer containing suitable nucleophilic groups. Amongst suitable nucleophiles there are polyacrylamides partially substituted with acylhydrazide groups, hydrazides of dicarboxylic acids, polyamines such as linear polyvinylamine, and various biologically active macromolecules having suitable functional groups for reaction with the dihaloisocyanide polymer. Amongst these there may be mentioned enzymes. Various suitable polymeric backbones may be used. Especially suitable are the various types of commercially available polyamides of the various nylon types (such as Nylon 6, Nylon 66, AA and AB-BB types), various polyesters and polymers of the urea-formaldehyde type. The novel dihaloisocyanide polymers can be used for the covalent bonding of biologically active proteins: ##STR3## wherein the --NH 2  group is part of the protein molecule. 
     The highly reactive insoluble polymeric dihaloisocyanide derivative is to a certain extent a polymeric structural analog of phosgene and this easily reacts with unprotonated forms of the nucleophilic groups present in proteins, and when the amine function of the protein undergoes reaction, a stable ureide type of bond is formed. With aromatic hydroxyls and with sulfhydryl groups there are obtained corresponding urethane and thiolurethan derivatives, respectively. 
     The haloisocyanide substituted polymer is highly reactive and when such polymer is powder form is added portionwise to a cold aqueous solution of a biologically active protein, as for example an enzyme, the reaction proceeds to completion in about 30 minutes in the cold. 
     The dihaloisocyanide polymers can be used as starting material for the prouction of various other products, by reaction with multifunctional reagents containing at least one nucleophilic group capable of reacting with the dihaloisocyanide moiety. For example, reaction with acylhydrazides to form 5-membered 1,3,4-oxadiazole type heterocyclic compounds can be utilized to prepare polymeric acylhydrazide derivatives: Dibromoisocyanide nylon was reacted with bifunctional adipic dihydrazide, which later can be converted to the corresponding azide by treatment with nitrous acid, and used for the covalent bonding of proteins. ##STR4## wherein R&#39; is a polymeric backbone and 
     R&#34; is the residue of a acyl hydrazide. 
     In a similar manner polymeric hydrazides can be grafted onto the surface of dibromo- or dichloro-substituted isocyanide polymers. For example, linear polyacrylamide in which a certain percentage (of about 5 to 10%) of the amide groups had been converted to acylhydrazide groups by controlled hydrazinolysis according to Inman (Inman J. K. and Dintizis H. M. Biochemistry 8, 4074 (1969), Inman J. K. Meth. Enzymol. 34, 40 (1974)), was reacted with dibromoisocyanide nylon to yield a novel polymeric carrier bearing acylhydrazide groups. The acylhydrazide groups can be used for the immobilization of enzymes by the azido method; the acylhydrazide groups can also be converted into other chemically active functional groups and the latter can be used for the immobilization of biologically active proteins. Conversion of the acylhydrazide to an arylamine followed by a diazotization can be used for the coupling of proteins via azo-bonds. 
     It is one of the main advantages of the present invention that: 
     a. the protein binding capacity, and 
     b. the specific activity 
     of the covalently bound protein is considerably higher with the polymer polyacrylamide grafts as compared with the ungrafted polymer. Furthermore, enzymes and other active molecules, bound to polyacrylamide graft-polymers exhibited enhanced storage and thermal stability. 
     The polymeric dihaloisocyanide derivatives can be used for grafting of other polymers containing other types of nucleophilic functional groups, such as for example by reacting bromoisocyanide nylon with linear polyvinylamine to give polyvinylamine nylon grafts. 
     The invention is illustrated in the following with reference to preparations wherein fine powders of isocyanide and dihaloisocyanide-substituted polymers obtained from polyamides, polyesters and urea-formaldehyde resins are used because of the favorable area to weight ratio of such material as support. Other polymers with ═N&#39;═C groups can be used in a similar manner. The polymers can be used in any desired form such as fibers, sheets, non-woven fabric etc. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     METHOD 
     1,6-diisocyanohexane was synthesized according to Goldstein et al (Biochem J. 143, 497 (1974)). The isocyanide content of polymers containing isonitrile functional groups was determined tritrimetrically by an adaptation of the method of Aurora et al (Z. Anal.Chem. 269, 124 (1974)). 
     Dibromoisocyanide groups were estimated by reacting the NCBr 2  polymers with excess dithioerythritol, the unreacted sulfhydryl groups being determined spectrophotometrically by the Ellman procedure (Arch. Biochem. Biophys. 82, 70 (1959)). 
     Acylhydrazide groups were determined by a two-step procedure, consisting of succinylation followed by the titrimetric determination of carboxyls, essentially as described by Inman (Meth. Enzymol. 34, 30 (1974)). 
     Bound protein was estimated by the Lowry method and confirmed by total amino acid analysis of acid hydrolyzates of the appropriate enzyme-polymer conjugate. The enzymatic activities of the trypsin, chymotrypsin, subtilisin BPN&#39;, and papain and of their insoluble conjugates were determined at 25° by the pH-statmethod (Golstein, Meth. Enzymol. 19, 915 (1970)). 
     The enzymic activity of urease and immobilized urease was determined by the nitropruside method according to Chaney and Marbach (Clin.Chem. 8, 130 (1962)). 
    
    
     EXAMPLE 1 
     ISOCYANIDE DERIVATIVES OF NYLON-(Polyisonitrile-nylon) 
     The isocyanide-derivative of nylon was prepared from partially hydrolyzed nylon powder essentially as described by Golstein et al (Biochem. J. 143, 497 (1974)). Nylon powder (2 gms) was suspended in 3 N HCl (60 ml), stirred for 4 hrs at room temperature, and then washed with water, methanol, and ether and air-dried. The partially hydrolyzed nylon powder (1 mg, 60-70 μmole COOH/gm) was suspended in propan-2-ol (40 ml). Isobutyral (16 ml) was then added, followed by 1,6-diisocyanohexane (4 ml; 0.03 mole) and the reaction allowed to proceed with stirring, in a closed vessel at room temperature, for 24 hrs. The polyisonitrile-nylon powder was separated by filtration, washed with methanol and ether and air-dried. The mean isocyanide content of the powder was 40-50 equiv×10 -6  /gm (See Table I). 
     EXAMPLE 2 
     ISOCYANIDE DERIVATIVES OF SYNTHETIC POLYESTERS 
     Isocyanide functional groups were introduced on the surface of poly(ethyleneterephthalate) powders of fibers by a three-step procedure, based on the Passerini reaction 
     R&#39;COOH+R 2  CHO+R 3  --NC→R&#39;COOCH(CONHR 3 )R 2   
     The methods consist of: 
     a. controlled alkaline hydrolysis to generate --COOH.HO-- pairs on the surface of the polyester structure, 
     b. conversion of the hydroxyl groups generated in the first step into aldehydes by controlled oxidation with dipyridyl chromium (VI)oxide according to Stensio (Acta Chem. Scand. (1971) 25, 1125-1128), and 
     c. resealing of the carboxyl-aldehyde pairs by a Passerini type reaction using 1,6-diisocyanohexane. 
     Procedure: 
     a. Poly(ethyleneterephthalate) powder (1 gm) was suspended in 0.01 N NaOH in 10% ethanol (50 ml) and stirred for 1 hr at 33°. The powder was separated by filtration, washed with water, 0.01 N HCl, water, methanol, ether, and air-dried. 
     b. The partially hydrolyzed polyester powder (1 ml) was suspended in glacial acetic acid (10 ml). An 0.8 M solution of dipyridyl chromium (VI) oxide was added and the reaction mixture stirred for 2 hrs. at room temperature. The powder was washed exhaustively with water, methanol, and ether and air-dried. 
     c. The oxidized poly(ethyleneterephthalate) powder obtained in the preceding step was suspended in ether (10 ml), 1,6-diisocyanohexane (1 ml) was added and the reaction allowed to proceed at room temperature for 18 hrs. The powder was separated, washed with ether, methanol and again with ether and air-dried. The mean isocyanide content of the powder was 40-50 equiv×10 -6  /gm. (See Table I). 
     EXAMPLE 3 
     ISOCYANIDE DERIVATIVES OF UREA-FORMALDEHYDE RESINS 
     Isocyanide functional groups were introduced on the surface of urea-formaldehyde resin powders using a two-step procedure: 
     a. mild acid hydrolysis to generate amino groups through degradation of ureide sequences on the surface of the polymer, 
     b. four-component condensation in the presence of acetic acid, isobutyral and 1,6-diisocyanohexane in methanol. 
     Procedure: 
     a. Urea-formaldehyde resin powder (1 gm) was suspended in 3 N HCl (20 ml) and stirred at room temperature for 45 min. The powder was separated and washed with water 0.1 N NaOH, methanol, and ether and air-dried. 
     b. Partially hydrolyzed urea-formaldehyde resin powder (1 gm) was suspended in methanol (5 ml). Glacial acetic acid (0.5 ml), isobutyral (0.5 ml) and 1,6-diisocyanohexane (1 ml) were added and the reaction allowed to proceed with stirring at room temperature for 18 hrs. The powder was separated, washed with methanol and ether and air-dried. The mean isocyanide content of the powder was 5-6 equiv×10 -6  /gm (See Table VIII). 
     The properties and protein binding capacities of the isocyanide polymers described in Examples 1 to 3 are summarized in Table I. 
     EXAMPLE 4 
     DIBROMOISOCYANIDE NYLON DERIVATIVES 
     Polyisonitrile-nylon powder (100 mg; 40-50 μmole --NC/gm) was suspended in chloroform (10 ml) and stirred magnetically for 10 min. over ice. A bromine solution (1 ml of a 1% solution in CHCl 3  ; 200 μmole Br 2 ) was added to the ice-cooled polymer suspension and stirred for 15 min. Triethylamine (0.2 ml) was then added with stirring (to remove unreacted bromine). The polymeric powder was separated on a suction filter, washed with cold chloroform and then with ether and air-dried. Due to its high reactivity, the dibromoisocyanide-nylon derivative (30-35 equiv×10 -6  --NCBr 2  /gm) was used immediately after preparation. (See Table II). 
     EXAMPLE 5 
     ACYLHYDRAZIDE-NYLON DERIVATIVES 
     Freshly prepared dibromoisocyanide nylon powder (100 mg; 30-35 μmole --NCBr 2  /gm) was added slowly to 10 ml of a vigorously stirred, ice-cooled, 0.02 M solution of adipic dihydrazide, brought to pH 8, and the reaction allowed to proceed under the pH-stat for 1 hr. The acylhydrazide-nylon powder was separated on a filter-washed with water, methanol, and ether and air-dried. The polymer (25-30 equiv.×10 -6  --CONH.NH 2  /gm) was stored in stoppered vials at room temperture. (See Table II). 
     EXAMPLE 6 
     POLYACRYLAMIDE-NYLON ACYLHYDRAZIDE DERIVATIVES 
     Freshly prepared dibromoisocyanide nylon powder (100 mg; 30-35 equiv.×10 -6  --NCBr 2  /gm) was added slowly to 10 ml of a vigorously stirred, ice-cooled solution of polyacrylamide-hydrazide (5 mg/ml; acylhydrazide content 5%) in 0.1 M ethylmorpholine buffer pH 8. The reaction was allowed to proceed for 1 hr with stirring. The polyacrylamide-nylon powder was separated by filtration and washed with water, ethanol, ether and air-dried. 
     EXAMPLE 7 
     POLYVINYLAMINE-NYLON ISOCYANIDE DERIVATIVE 
     a. Freshly prepared dibromoisocyanide nylon powder (100 mg; 30-35 equiv.×10 -6  --NCBr 2  /gm) was added slowly to 5 ml of a vigorously stirred, ice-cooled solution of polyvinylamine (30 mg/ml) in 0.2 M N-ethylmorpholine buffer pH 9. The reaction was allowed to proceed with stirring for another 30 min. The polyvinylamine-nylon powder was separated on a filter and washed with water, methanol, and ether and air-dried. 
     b. Polyvinylamine-nylon (100 mg) was suspended in methanol (5 ml). An 0.1% (v/v) solution of isobutyral in methanol (0.2 ml) was added and the suspension stirred for 30 min. at room temperature. 1,6-diisocyanohexane (0.25 ml) and glacial acetic acid (0.15 ml) were then added and the reaction allowed to proceed for 18 hrs. at room temperature. The powder was separated on a filter, washed with methanol, and ether and air-dried. The isocyanide content of the powder was 15-20 equiv.×10 -6  /gm. The properties and protein binding capacity of the isocyanide derivatives of polyvinylamine nylon are given in Table I. 
     EXAMPLE 8 
     CHEMICAL MODIFICATION OF SPUN-BONDED NYLON FABRIC SHEETS 
     Discs of 30 mm diameter were cut from spun-bonded nylon fabric sheets (Cerex®, Monsanto Company) and packed in a glass column (height-50 mm; internal diameter 30 mm) fitted with a fritted glass disc at the bottom and a ground-glass adapter at the top. Constant packing of the discs was maintained by means of an additional fritted-glass disc, held in place by teflon rings of the appropriate thickness. By this arrangement all chemical modification reactions as well as the coupling of enzymes could be carried out consecutively, by circulating the appropriate reagents through the column. 
     a. Isocyanide-nylon derivatives: 3 N HCl (100 ml) was perfused through a column containing 100 discs (about 6 gms net, Cerex®) to remove impurities, and 3 N HCl was circulated for 4 hrs at room temperature at a rate of 12-15 ml/min. The column was washed by perfusing water (300 ml) methanol (100 ml) and ether (100 ml). A solution of 1,6-diisocyanohexane (3.3 μl) and isobutyral (13.2 ml) in isopropanol (33 ml) was then circulated at a rate of 0.5-1 ml/min at room temperature, overnight. The column was washed with methanol (100 ml) and ether (200 ml). 
     b. Dibromoisocyanide-nylon: An ice-cooled 0.1% solution of bromine in chloroform (100 ml) was perfused through a column packed with isocyanide-nylon discs, in the course of 30 min. To remove unreacted bromine, the column was washed with the following ice-cold solutions: chloroform (30 ml), 2% triethylamine in chloroform (25 ml), chloroform (30 ml) and ether (50 ml). Due to the high reactivity of the --NCBr 2  groups, the dibromoisocyanide-nylon discs were used immediately for the next step. 
     EXAMPLE 9 
     ACYLHYDRAZIDE DERIVATIVES OF NYLON FABRIC DISCS 
     An ice-cooled 0.05 M solution of adipic dihydrazide in 0.01 M N-ethylmorpholine buffer, pH 8 (50 ml) was perfused through a column packed with dibromoisocyanide-nylon discs; the effluent was collected, the pH brought back to 8, and the reagent solution recirculated through the column for 1 hr at a rate of 5-10 ml/min with cooling. The column was washed with water (300 ml), methanol (100 ml) and ether (50 ml). 
     EXAMPLE 10 
     AMINOARYL DERIVATIVES OF NYLON FABRIC DISCS 
     Aminoaryl derivatives of nylon fabric discs were prepared from isocyanide-nylon utilizing the four-component reaction previously described (1,3). Through a column packed with isocyanide-nylon discs a methanolic solution (40 ml) containing 4,4&#39;-diaminodiphenyl-methane (400 mg; 2 mmole), isobutyral (0.1 ml; 1 mmole) and acetic acid (0.2 ml; 3.5 mmole) was circulated at room temperature, for 18 hrs at a rate of 0.5-1 ml/min. The column was washed with dimethylformamide (100 ml), methanol (200 ml) and ether (100 ml). 
     EXAMPLE 11 
     ACYLHYDRAZIDE DERIVATIVES OF POLYACRYLAMIDE-NYLON DISCS 
     An ice-cooled solution of polyacrylamide hydrazide (5 mg/ml; acylhydrazide content about 5%) in 0.01 M N-ethylmorpholine buffer, pH 8 (40 ml) was perfused through a column packed with dibromoisocyanide-nylon discs; the effluent was collected, the pH brought back to 8, and the cooled polyacrylamide solution recirculated through the column for 2 hrs at a rate of 12 ml/min. The column was washed with water (300 ml), methanol (50 ml) and ether (50 ml). 
     EXAMPLE 12 
     AMINOARYL DERIVATIVES OF POLYACRYLAMIDE-NYLON DISCS 
     The aminoaryl derivative of polyacrylamide-nylon was prepared from the corresponding acyl-hydrazide derivative via the acylazide method. 
     An ice-cooled 1% solution of sodium nitrite in 0.1 M HCl (50 ml) was perfused through a column packed with polyacrylamide-nylon acylhydrazide discs at a rate of 2-3 ml/min. The activated column was washed with cold water (100 ml) and reacted immediately with a 4,4-diaminodiphenyl methane solution (50 ml) circulated through the column at 4° for 18 hrs. The reagent solution was prepared by dissolving 0.5 gms. 4,4&#39;-diaminodiphenyl methane in 25 ml dimethylformamide followed by the addition of 25 ml water with stirring, the pH being adjusted to 9.0. The column was washed with dimethylformamide (100 ml) water (200 ml) methanol (100 ml) and ether (50 ml). 
     EXAMPLE 13 
     CHEMICAL MODIFICATION OF NYLON-FIBERS 
     Commercial nylon 6,6 fibers (3 gms overall weight) were packed in a glass tube (6 mm internal diameter, 40 cm length), in parallel to the tube&#39;s axis. The fibers were washed by perfusing 300 ml ether, in the course of 2 hrs to remove lubricants. All further manipulations were carried out as described for nylon fabric discs. 
     EXAMPLE 14 
     COUPLING OF ENZYMES TO POLYISONITRILE-NYLON POWDER 
     Polyisonitrile-nylon powder (50 mg) was suspended in 2 ml of a cold enzyme solution (10 mg protein) in 0.1 M sodium phosphate 0.5 M sodium acetate pH 7.5. Cold acetaldehyde (0.1 ml) was then added and the reaction allowed to proceed overnight with stirring at 4°. The insoluble enzyme derivative was separated by filtration, washed with water, 1 M KCl and again with water, resuspended in water (4 ml) and stored at 4°. 
     The results for several enzymes are summarized in Tables 1 and IV. 
     EXAMPLE 15 
     BINDING OF ENZYMES TO DIBROMOISOCYANIDE-NYLON POWDER 
     Freshly prepared dibromoisocyanide-nylon powder (50 mg) was added in the course of 10 min to a magnetically stirred, ice-cooled solution of enzyme (10 mg) in 2 ml 0.2 M N-ethylmorpholine buffer pH 8.0. The reaction was allowed to proceed for 20 min. The insoluble enzyme derivative was separated by filtration, washed and stored as described above. The results for several enzymes are summarized in Tables III and IV. 
     EXAMPLE 16 
     COUPLING OF ENZYMES TO ACYLHYDRAZIDE-NYLON POWDER 
     Acylhydrazide-nylon powder (50 mg) was suspended in 5 ml cold 0.1 M HCl. Sodium nitrite (50 mg) was then added and the reaction mixture stirred for 30 min. over ice. The acylazide-nylon derivative was separated by filtration, washed exhaustively with cold water and added to a cold solution of the enzyme (10 mg/2 ml) in 0.1 M N-ethylmorpholine buffer pH 9. The reaction was allowed to proceed overnight, with stirring at 4°. The immobilized enzyme derivative was separated by filtration, washed and stored as described above. The results for several enzymes are summarized in Table IV. 
     EXAMPLE 17 
     COUPLING OF AMINO ACIDS AND PEPTIDES TO DIBRIOMOISOCYANIDE-NYLON POWDER 
     Freshly prepared dibromoisocyanide-nylon powder (40 mg) was added in the course of 10 min to a magnetically stirred, ice-cooled, 0.01 M solution of an amino acid derivative or peptide (10 ml), under the pH-stat, set at the appropriate pH. The reaction was allowed to proceed for 20 min, the insoluble derivative was separated by filtration, washed exhaustively with water, methanol and ether and air-dried. The results for several peptides and mixtures thereof are summarized in Table V. 
     EXAMPLE 18 
     COUPLING OF ENZYMES TO ACYLHYDRAZIDE DERIVATIVES OF NYLON AND POLYACRYLAMIDE-NYLON DISCS 
     An ice-cooled 1% solution of sodium nitrite in 0.1 N HCl (100 ml) was perfused through a column packed with nylon- or polyacrylamide-nylon-acylhydrazide discs at a rate of 2-3 ml/min. The activated column was washed with cold water (100 ml). An enzyme solution (5 mg/ml; 40 ml) in 0.1 M N-ethylmorpholine buffer pH 9.0 was then circulated through the column, at 4° for 18 hrs. The column was washed with cold water (500 ml), 1 M KCl (200 ml) and water (100 ml). The enzyme nylon discs were stored under water at 4°. The results for several enzymes are summarized in Tables VIa and VIb. Chymotrypsin and Subtilisin BPN&#39; bound to nylon and polyacrylamide nylon were tested as regards temperature stability. Tests proved that the latter were inactivated at substantially higher temperatures (difference up to about 20° C.). 
     EXAMPLE 19 
     COUPLING OF ENZYMES TO AMINOARYL DERIVATIVES OF NYLON AND POLYACRYLAMIDE NYLON DISCS 
     A column packed with aminoaryl-, nylon or polyacrylamide-nylon discs was activated by circulating 1% sodium nitrite as described above. The activated column was washed with cold water (100 ml). An enzyme solution (5 mg/ml; 40 ml) in 0.1 M phosphate buffer pH 8 was circulated through the column at 4° for 18 hrs. The enzyme-nylon discs were washed and stored as described above. The results for several enzyme are summarized in Tables VIa and VIb. 
     
                                           TABLE I__________________________________________________________________________COUPLING OF TRYPSIN TO ISOCYANIDE DERIVATIVES OF NYLONPOLY(ETHYLENETEREPHTHALATE)UREA-FORMALDEHYDERESIN AND POLYVINYLAMINE-NYLON VIAFOUR COMPONENT CONDENSATION REACTIONS.sup.(a)         Mean particle     Total Bound                                   Active Bound         Diameter                 Isocyanide content                           Protein ProteinSupport material         (microns)                 (equiv × 10.sup.6 /gm)                           mg/gm support                                   (% of total)__________________________________________________________________________Nylon 6       0.7     45        150     56Poly(ethyleneterephthalate)         9       40        93      30Urea-formaldehyde Resin         200     4.8       13      38Polyvinylamine nylon         0.7     15        50      40__________________________________________________________________________ .sup.(a) Coupling mixture: 100 mg polymer and 20 mg trypsin in 4 ml 0,1M phosphate. 0.5M acetate pH 7.5 containing 0.2 ml acetaldehyde - 
    
     
                                           TABLE II__________________________________________________________________________CHARACTERIZATION OF CHEMICALLY MODIFIED NYLONSIsocyanide- Dibromoisocyanide-NylonNylon DerivativeDerivative effective       Acylhydrazide-Nylon--NC  --NCBr.sub.2    Derivativecontent content      efficiency of         efficiency of(equiv × (equiv ×      conversion --CONH.NH.sub.2 content                            conversion     overall yield10.sup.6 /gm) 10.sup.6 /gm)      --NC→--NCBr.sub.2 (%)                 (equiv × 10.sup.6 /gm)                            --NCBr.sub.2 →--CONH.NH.sub.2                                           --NC→--CONH.NH.sub.                                           2 (%)__________________________________________________________________________44    31   71         27         87             61__________________________________________________________________________ 
    
     
                       TABLE III______________________________________COUPLING OF ENZYMES TO ADIBROMOISOCYANIDE DERIVATIVE OF NYLON         Bound Protein                        Active    pH of  Total bound  Bound Protein      coupling Protein      mg/gm % ofEnzyme     reaction mg/gm support                            support                                  total______________________________________Trypsin    7        13.1         2.0   15      8        14.2         5.5   39      9        21.0         14.2  68Chymotrypsin      7        10.0         1.6   16      9        15.3         10.0  66Subtilism BPN&#39;      7        3.3          0.14   4      9        9.3          1.14  12Papain     7        26.6         3.9   15      9        23.4         11.4  49______________________________________ 
    
     
                                           TABLE IV__________________________________________________________________________BINDING OF ENZYMES TO NYLON SUPPORTS CARRYINGDIFFERENT FUNCTIONAL GROUPS.sup.(a)                 Modified Nylon.sup.(b)                 Dibromoisocyanide   Isocyanide Derivative.sup.(c)                 Derivative.sup.(d)                               Acylhydrazide Derivative.sup.(e)   Total         Total         Total   bound        Active bound                 bound                      Active bound                               bound                                    Active bound   protein        protein  protein                      protein  protein                                    protein   (mg/gm        mg/gm             %   (mg/gm                      mg/gm                           %   (mg/gm                                    mg/gm                                        %Enzyme  support)        support             of total                 support)                      support                           of total                               support)                                    support                                        of total__________________________________________________________________________Trypsin 48   30   68  21   14.2 68  16.2 14.4                                        80Chymotrypsin   45   10   22  15.2 10   66  13.6 10  74Subtilisin BPN&#39;   14.4  5   35  9.2  1.2  13  8.6  2.8 33Papain  70   32   46  23.4 11.4 49  29.2 12.2                                        42__________________________________________________________________________ .sup.(a) All coupling mixtures contained 10 mg protein and 50 mg derivatizednylon powder in 2 ml of the appropriate buffer. .sup.(b) Details on chemical characteristics of derivatizednylon powders are given in Table II. .sup.(c) Coupling of proteins carried out by four component condensation at pH 7.5. .sup.(d) Coupling of protein carried out at pH 9. .sup.(e) Coupling of protein carried out at pH 9. 
    
     
                       TABLE V______________________________________COUPLING OF MODEL PEPTIDES TODIBROMOISOCYANIDE-NYLONPeptides         Amino Acid Boundin               (μmoles/gm support)Reaction Mixture        pH      Leu    His    Tyr  Total______________________________________Leu NH.sub.2 7       2.2    --     --   2.2        8       9.5    --     --   9.5        9       9.5    --     --   9.5PhCO.Gly.His 6       --     8.4    --   8.4        7       --     11.8   --   11.8        8       --     11.5   --   11.5        9       --     11.3   --   11.3AcTyrOEt     8       --     --     9.1  9.1        9       --     --     12.8 12.8Leu NH.sub.2 7       1.2    10.1   --   11.3PhCO.Gly.His 9       4.3    6.7    --   11.0Leu NH.sub.2 8       3.8    --     4.9  8.7+AcTyrOEt     9       3.3    --     6.5  9.8PhCO.Gly.His 6       --     7.2    0.8  8.0+            7       --     10.1   1.1  11.2ACIyrOEt     8       --     8.9    2.4  11.3        9       --     3.6    7.6  11.2Leu NH.sub.2 7       1.2    9.6    1.0  11.8PhCO.Gly.His 9       2.1    3.6    6.2  11.9+AcTYrOET______________________________________ 
    
     
                       TABLE VIa______________________________________BINDING OF ENZYMES TO NYLON FABRIC SHEETS.sup.(a)           Total Bound                      Active   Type of Protein    Bound ProteinEnzyme    Support   (mg/gm)    mg/gm % of Total______________________________________A. ACYLHYDRAZIDE DERIVATIVESTrypsin   Nylon     0.29       0.10  35     PAA-nylon 1.56               0.72       46Chymotrypsin     Nylon     0.24       0.09  37     PAA-nylon 1.10       0.54  49Subtilisim BPN&#39;     Nylon     0.16       0.04  26     PAA-nylon 0.48       0.25  53Papain    Nylon     0.35       0.15  43     PAA-nylon 2.64       2.16  82B. AMINOARYL DERIVATIVESTrypsin   Nylon     0.33       0.14  30     PAA-nylon 0.50       0.38  77Papain    Nylon     0.52       0.21  40     PAA-nylon 2.16       1.53  71Urease    Nylon     1.00       0.82  82     PAA-nylon 8.16       7.33  90______________________________________ .sup.(a) Coupling of enzyme was carried out by circulating 40 ml of a col enzyme solution (5 mg/ml) through a column loaded iwth nylon or polyacrylamidenylon fabric discs; PAAnylon, polyacrylamidenylon graft. 
    
     
                       TABLE VIb______________________________________ENRICHMENT FACTORS FOR TOTAL PROTEIN ANDSPECIFIC ACTIVITY OF ENZYMES BOUND TOPOLYACRYLAMIDE-NYLON FABRIC SHEETS.sup.(a)              Total     Specific                               Total     Coupling Protein   Activity                               Activity.sup.(b)Enzyme    Method   (A)       (B)    (C)______________________________________Trypsin   acylazide              5.44      1.31   7.12     diazo    1.29      2.13   2.75Papain    acylazide              7.54      1.92   14.5     diazo    4.12      1.77   7.31Chymotrypsin     acylazide              4.59      1.33   0.12     diazo    --        --     --Subtilisin     acylazide              2.96      2.00   5.80BPN&#39;     diazo    --        --     --Urease    acylazide              --        --     --     diazo    8.16      1.10   8.96______________________________________ .sup.(a) Enrichment factors calculated from data of Table VIa (value for polyacrylamidenylon enzyme conjugate)/(value for ungrafted nylonenzyme conjugate). .sup.(b) Calculated from C = A.B.