Ahmad Salahuddin

Professor Ahmad Salahuddin
(7 July1937-26 November 1996) was a biochemist from India and served as a Professor of Biochemistry and department chairman (1984-1996) at Aligarh Muslim University (AMU) Aligarh, India. AMU Aligarh 
== Early Life ==
Dr. Salahuddin was born on July 7, 1937 in the town of Azamgarh, Uttar Pradesh, India. Dr. Salahuddin's father, Fazlul Bari, was a teacher at the Shibli National College, Azamgarh, where he received his early education.
== Education ==
Dr. Salahuddin joined AMU, Aligarh in 1954 where he completed his undergraduate and Master's degree in 1956 and 1958 respectively in Chemistry. Initially, he took interest in Physical Chemistry, joining the laboratory of Professor Wahid U. Malik, Department of Chemistry, AMU and was awarded a Ph.D. degree in Chemistry in 1962.
== Career ==
===Chemistry Department, Faculty of Science, AMU, Aligarh===
Starting in 1962, he worked as a lecturer in the Department of Chemistry at AMU. He taught Physical Chemistry to undergraduate students. Notably, he was selected for the Fulbright Fellowship program from India while working at the university. As a Fulbright Fellow, he worked in the laboratory of Professor Charles Tanford, a protein biochemist at Duke University in the United States from 1964 to 1968. He studied the biochemistry of protein folding i.e. a complex mechanism of the formation of native structure from a linear random coil protein at ribosomes in the living cells. The primary structure i,e, the amino acid sequence in the linear form of the protein is essential for the formation of the native globular protein, thermodynamically the most stable structure under the physiological conditions. In order to learn in vitro protein folding, he characterized structures in model proteins experimentally after heat and acid (low pH) treatment. He found that the heat and acid treated proteins contained residual native structures which were disrupted by treatment with the potent denaturant guanidine hydrochloride as shown by steep denaturation curves characteristic to an equilibrium between residual native structure and random coil protein in guanidine hydrochloride for each model protein. Evidence for residual structure in acid and heat denatured proteins, by Aune, KC, Salahuddin A, Zarlingo, MH and Tanford C. Department of Biochemistry, Duke University Medical Centre NC 27706 USA https://web.archive.org/web/20190712182255id_/http://www.jbc.org:80/content/242/19/4486.full.pdf He spent four years in Dr. Tanford's lab, and his work on lysozyme protein was found to be suitable by Duke university for awarding him Ph.D in Biochemistry in 1968. A. Salahuddin (1968) Thermodynamics of the Denaturation of Ribonuclease by Guanidine Hydrochloride, Ph.D. Thesis, Duke University, Durham NC U.S.A and by A. Salahuddin and C. Tanford, Biochemistry 1970, 9, 6, 1342–1347 https://pubs.acs.org/doi/abs/10.1021/bi00808a007
=== Department of Biochemistry, J.N. Medical College, Faculty of Medicine, AMU===
In 1968, he returned to AMU and joined the Department of Biochemistry in the Faculty of Medicine as a reader. He taught biochemistry and supervised PhD students, establishing a Protein Research Laboratory in the department.
=== Studies on Protein Folding and Protein-Protein Interaction:===
Dr. Salahuddin supervised Ph.D. students, who worked on in vitro protein folding (or protein denaturation), among other subjects. The denaturation of egg white ovalbumin, as a model protein, was followed by measuring changes in the properties of UV absorption spectrum and viscosity of protein induced by guanidine hydrdrochloride. The transition of ovalbumin from native (N) in the absence of denaturant to the denatured protein in random coil structure (D) proceeded in a narrow range of denaturant concentration in the form a single steep transition curve; 100% (D) existed at high ~ 6 M Guanidine hydrochloride. The N to D transition curve was found to be reversible with a characteristic equilibrium constant, at a constant temperature. Energy equations were applied to this reversible reaction and a negative energy change was found in the favour of native structure as opposed to denatured form. The transition was dependent on temperature and native structure was favoured at relatively higher than lower temperatures. The results suggested that the native structure is stabilized by hydrophobic forces in the aqueous solution. F. Ahmad and A. Salahuddin (1976) Reversible unfolding of the major fraction of ovalbumin by Guanidine Hydrochloride. Biochemistry (U.S.A.)15, 5168-5175
https://pubs.acs.org/doi/pdf/10.1021/bi00668a034 
As opposed to ovalbumin, the denaturation of egg white ovomucoid protein did not proceed in a single step but occurred in two steps; the transition at low denaturant was associated with a globular protein structure with less unfolded random coil structure, and at high denaturant concentration protein existed in random coil structure. M.A. Baig and A. Salahuddin (1978). Occurrence and characterization of stable intermediate state(s) in the unfolding of ovomucoid by Guanidine Hydrochloride. Biochem J. (U.K.) 171-89-97 https://pubmed.ncbi.nlm.nih.gov/646827/ The structural transition of domains in bovine serum albumin together and separately were compared in denaturation studies. M. Yahya Khan and A. Salahuddin (1984). Lack of N→F transition in the N-terminal fragment (domain I and II) of bovine serum albumin. Eur. J. Biochem (Germany) 141, 473-475 https://pubmed.ncbi.nlm.nih.gov/6745254/ These studies on denaturation of the above proteins namely egg white ovomucoid and bovine serum albumin,in particular, in his lab succeeded characterize multiple globular proteins distinguishable from the most stable native protein structure. However, it is not clear whether these less stable proteins are formed together with the most stable ones as a result of in vivo folding with the help of factors (i.e. chaperones) at the ribosome where transcripts are translated into linear proteins. Botao Liu, Crystal S Conn, and Shu-Bing Qian, Viewing folding of nascent polypeptide chains from ribosomes Expert Rev Proteomics. 2012 Dec; 9(6): 579—581 https://doi.org/10.1586/epr.12.57
Interestingly, the hydrophobic effect was involved in protein-protein interactions as studied by egg albumin with anti egg albumin antibody system. A.A. Ansari and A. Salahuddin (1973). Effect of pH, Ionic strength and temperature on the albumin-antioalbumin precipitin reaction. Immunology (U.K.)25, 377-383 https://pubmed.ncbi.nlm.nih.gov/4742047/ 
=== Enzymology / Studies on Enzymes: ===
Dr. Salahuddin's team also studied enzyme systems under native states and additionally some of the mammalian enzymes were successfully purified in his lab. This included buffalo muscle aldolase, an enzyme involved in glycolytic pathway with substrate preference comparable to an aldolase prepared from a known eukaryotic species, rabbit muscle; S.T. Pasha and A. Salahuddin (1977. Isolation of buffalo muscle aldolase and comparison of its properties with those rabbit muscle aldolase. Biochim. Biophys. Acta.(Netherlands) 483,435-442. https://pubmed.ncbi.nlm.nih.gov/19072/ Cathepsin purification, substrate specificity and the critical role of sulfhydryl group that was compatible with in vivo function reported for known proteins. A. Salahuddin, F.A. Siddiqi and P. Salahuddin (1996). Isolation, puriﬁcation and properties of cathepsin B from buffalo liver. Indian J. Biochem. Biophys.33(4),292-7. https://pubmed.ncbi.nlm.nih.gov/8936819/ 
===Lectin and carbohydrate interactions and in vitro characterization of membrane proteins and receptors:===
Briefly, Dr. Salahuddin had a long term goal of studying lectins and cell membrane proteins. Two lectins i.e., a plant based Concanavalin A A. Waseem and A. Salahuddin (1983). Anomalous temperature dependence of the specific interaction of Concanavalin A with multivalent ligand-Dextrin. Biochim Biophys. Acta (Netherlands) 746, 65-71 https://www.sciencedirect.com/science/article/abs/pii/0167483883900110 , and lectins from mammalian sources i.e. liver were purified in native states. The correct molecular characterization and distinct carbohydrate binding specificity for each lectin system, were established in his lab. Najma Ali and A. Salahuddin (1989). Isolation and some properties of mammalian hepatic membrane lectins. FEBS Lett. (Netherlands) 246, 163-165 https://www.sciencedirect.com/science/article/pii/0014579389802753 Najma Ali and A. Salahuddin (1989). Isolation and characterization of soluble beta galactoside-binding lectins from mammalian liver. Biochim. Biophys. Acta (Netherland) 992-30-34 https://www.sciencedirect.com/science/article/abs/pii/0304416589900469 
===Allosteric protein===
Dr. Salahuddin served as visiting Associate Professor, University of Maryland, Baltimore, USA from 1975 to 1976: He worked on human hemoglobin which is an allosteric protein. Allosteric effectors usually bind to both deoxy-Hb and carboxyhemoglobin (HbCO), albeit at different sites, leading to a lowered oxygen affinity. The manner in which these effectors impact oxygen binding is unclear and may involve changes in structure. It is noted that Dr. Salahuddin and his group suggested conformational changes in HbCO and CO-ligated/3-chain tetramers from the observation of unusually steep oxygen saturation/pH curves obtained for the binding of allosteric effector benzene hexacarboxylate to ligated hemoglobin. A. Salahuddin and E. Bucci (1976). Conformational aspects of the interaction of polyanions with ligended beta chains of human hemoglobin. Biochemistry, 15, 3399-3405 https://pubs.acs.org/doi/pdf/10.1021/bi00661a001
=== Establishment of Interdisciplinary Biotechnology Unit (IBU), Faculty of Medicine ===
Establishment of the Interdisciplinary biotechnology Institute for modern Biological and Biotechnological education at the Medicine Faculty by the AMU administration in 1984 was a notable achievement in the career of Professor Salahuddin. He acted as a leader and Founder Director of the institute. As a result the Interdisciplinary Biotechnology Institute is functioning in fulfilling an educational need of the people of Uttar Pradesh, India.
==Honours==
Honours included: President of Society of Biological Chemists SBC (India) from the period 1989-1990; Member of the Editorial Board of Indian Journal of Biochemistry and Biophysics IJBB(1985-1988);Member of Protein Society, Bethesda, USA(1995-1997);Member of the New York Academy of Science, New York(1995-1996);Member of the Executive Committee of the Society of Biological Chemists, India(1974-1975);Member of the Executive committee of Indian Biophysical Society, India (1991-1993);Member of the Guha Research Conference, India (1987-1992)and Member of the Society of Sigma Xi (USA).
Category:1937 births
Category:Biochemists