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Schulman and Buchanan 196 (2): 513 Williams and Buchanan 202 (1): 253 Korn and Buchanan 217 (1): 183 J. Biol. Chem., Vol. 281, Issue 44, 35, November 3, 2006
Classics Biosynthesis of the Purines: the Work of John M. Buchanan
Biosynthesis of the Purines. II. Metabolism of 4-Amino-5-imidazolecarboxamide in Pigeon Liver
Biosynthesis of the Purines. IV. The Metabolism of 4-Amino-5-imidazolecarboxamide in Yeast
Biosynthesis of the Purines. VI. Purification of Liver Nucleoside Phosphorylase and Demonstration of Nucleoside Synthesis from 4-Amino-5-imidazolecarboxamide, Adenine, and 2,6-Diaminopurine John Machlin Buchanan was born in Winamac, Indiana in 1917. He attended DePauw University in Greencastle, Indiana, where he received his A.B. in 1938. Buchanan then started his graduate studies in the Department of Biological Chemistry at the University of Michigan. The chairman of the department, Howard B. Lewis, was one of the pioneers of research in intermediary metabolism, and he greatly influenced Buchanan. Buchanan recalls, "It was probably here and because of him that I cultivated an interest in this area of biochemistry. Yet I realized that many questions remaining about metabolic pathways could not be answered by techniques generally available at that time (1)." Buchanan earned his M.S. in 1939 and then moved on to Harvard University where he worked with Journal of Biological Chemistry (JBC) Classics author A. Baird Hastings (2). At Harvard, Buchanan studied glycogen synthesis in rats using [11C]lactic acid. An account of Buchanan's research in Hasting's laboratory can be found in his JBC Reflections (3). Buchanan earned his Ph.D. in 1943. Upon graduating, he became an Instructor in the Department of Physiological Chemistry at the University of Pennsylvania School of Medicine. He was promoted to Assistant Professor in 1946, Associate Professor in 1949, and Professor in 1950. In the mid-1950s, Buchanan helped to elucidate the pathways of purine biosynthesis and published a 20+-paper series in the JBC on the subject. G. Robert Greenberg did parallel research and sharing of information between the groups made for rapid progress. The three JBC Classics reprinted here have been selected from Buchanan's "Biosynthesis of the Purines" series. By 1952, it had been shown that 4-amino-5-imidazolecarboxamide (carboxamide) could be converted to hypoxanthine by pigeon liver homogenates and that inosinic acid might be an intermediate in the biosynthesis of hypoxanthine from formate. Buchanan decided to investigate the conversion of carboxamide to hypoxanthine in pigeon liver homogenates and extracts in order to determine whether ribotide formation was involved in carboxamide metabolism. This is the subject of the first JBC Classic reprinted here. By incubating radioactive glycine or carboxamide with pigeon liver homogenates or extracts, Buchanan was able to show that the carboxamide was utilized for hypoxanthine synthesis. He also found that units of ribose and phosphate were added to the carboxamide prior to ring closure. In the second JBC Classic reprinted here Buchanan shows that carboxamide is incorporated into purines in yeast as well as in mammals. Buchanan's studies on the incorporation of hypoxanthine into inosinic acid became the first example of the so-called salvage pathway or rescue of purine bases by direct conversion to their ribonucleotides.
In the final JBC Classic reprinted here Buchanan and JBC Classics author Edward D. Korn (4) demonstrate the conversion of carboxamide to its riboside, providing further evidence in support of the above proposed metabolic pathway for the conversion of the carboxamide to its ribotide and to inosinic acid in pigeon liver. In the paper, Buchanan and Korn show that 4-amino-5-imidazolecarboxamide, adenosine, and 2,6-diaminopurine can be converted to their ribosides by nucleoside phosphorylase in the presence of ribose 1-phosphate. This information, combined with Greenberg's observation that the riboside can be phosphorylated by adenosine triphosphate in pigeon liver preparations, provided a pathway for the conversion of free bases to their respective nucleotides via their nucleosides.
In 1953 Buchanan left the University of Pennsylvania to become Head of the Biochemistry Program in the Department of Biology at the Massachusetts Institute of Technology. He remained at MIT for the rest of his career, becoming Wilson Professor of Biochemistry in 1967 and Wilson Professor Emeritus in 1988. Buchanan received many awards for his research including the American Chemical Society's Eli Lilly Award in Biological Chemistry in 1951, the Harvey Society lectureship in 1958, and honorary doctorate degrees from the University of Michigan and DePauw University. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences. Buchanan was Secretary of the American Society for Biological Chemists (now American Society for Biochemistry and Molecular Biology) from 1969 to 1972 and served on the editorial boards of several journals, including the Journal of Biological Chemistry (19611967), the Journal of the American Chemical Society (19611972), and Physiological Reviews (19571960 and 19651971).1
FOOTNOTES
1 Biographical information on John M. Buchanan was taken from Refs. 1 and 3.
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