Abstract
It is shown that the transfer of formyl units in the de novo purine biosynthetic pathway as catalyzed by glycinamide ribonucleotide (GAR) transformylase and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase probably proceeds through a direct displacement mechanism involving only formyl donor (10-CHO-H4folate) and formyl acceptor (GAR or AICAR). The inability to observe enzyme-catalyzed solvent oxygen incorporation or uncoupling by hydroxylamine of 1:1 stoichiometry between formylated acceptor [formylglycinamide ribonucleotide or 5-(formylamino)imidazole-4-carboxamide ribonucleotide] and deformylated donor implies the absence of an amidine intermediate and suggests that either a formylated enzyme-bound intermediate is not formed or such an intermediate is not accessible to hydroxylamine.
Original language | English (US) |
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Pages (from-to) | 2870-2874 |
Number of pages | 5 |
Journal | Biochemistry |
Volume | 21 |
Issue number | 12 |
DOIs | |
State | Published - Jun 1982 |
All Science Journal Classification (ASJC) codes
- Biochemistry