On the purification and mechanism of action of 5-aminoimidazole-4-carboxamide-ribonucleotide transformylase from chicken liver

The transformylase from chicken liver catalyzing the formylation of 5-aminoimidazole-4-carboxamide ribonucleotide through the agency of 19-formyltetrahydrofolate has been purified to apparent homogeneity. Inosinicase activity copurifies. This transformylase is not further activated kinetically by th...

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Bibliographic Details
Published in:Biochemistry (Easton) 1981-01, Vol.20 (2), p.337-344
Main Authors: Mueller, W. Thomas, Benkovic, Stephen J
Format: Article
Language:English
Subjects:
Acyltransferases - isolation & purification
Acyltransferases - metabolism
Animals
Chickens
Cross-Linking Reagents - pharmacology
Hydroxymethyl and Formyl Transferases
Imidoesters - pharmacology
Kinetics
Liver - enzymology
Macromolecular Substances
Magnetic Resonance Spectroscopy
Phosphoribosylaminoimidazolecarboxamide Formyltransferase
Proteins - physiology
Spectrophotometry, Ultraviolet
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Summary:The transformylase from chicken liver catalyzing the formylation of 5-aminoimidazole-4-carboxamide ribonucleotide through the agency of 19-formyltetrahydrofolate has been purified to apparent homogeneity. Inosinicase activity copurifies. This transformylase is not further activated kinetically by the presence of the trifunctional protein in contrast to the glycinamide ribonucleotide transformylase. The enzyme exhibits a greater than 1000-fold preference for the naturally occurring 10-formyltetrahydrofolate cofactor and a sequential reaction pattern. A reinvestigation of the chemical structure of the formylated ribotide product employing 13C and 1H NMR indicated that the imidazole ring remained intact upon formylation, consistent with the originally proposed structure.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00505a017