Activity of formylphosphate in the reaction catalyzed by formyltetrahydrofolate synthetase
Formylphosphate (FP), a putative enzyme-bound intermediate in the reaction catalyzed by N/sup 10/-formylH/sub 4/folate synthetase, was synthesized from formylfluoride and Pi. Measurement of hydrolysis rates by /sup 31/P NMR showed that FP is very unstable with a half-life of 48 min at 20/sup 0/C and pH 7. At pH 7 hydrolysis occurs with O-P bond cleavage as shown by /sup 18/O incorporation from /sup 18/O-H/sub 2/O into Pi. The substrate activity of FP was tested in the reaction catalyzed by N/sup 10/-formylH/sub 4/folate synthetase isolated from Clostridium cylindrosporum. MgATP + H/sub 4/folate + HCOO/sup -/ in equilibrium MgADP + Pi +N/sup 10/-formylH/sub 4/folate FP supports the reaction in both the forward and reverse directions. Thus, N/sup 10/-formylH/sub 4/folate is produced from H/sub 4/-folate and FP but only if ADP is present, and ATP is produced from FP and ADP but only if H/sub 4/folate is present. The requirements for H/sub 4/folate in the synthesis of ATP from ADP and FP and for ADP in the synthesis of N/sup 10/-formylH/sub 4/folate from FP and H/sub 4/folate, are consistent with past kinetic and isotope exchange studies which showed that the reaction proceeds by a sequential mechanism and that all three substrates must be present for any reaction to occur.
- Research Organization:
- Univ. of Kansas, Lawrence
- OSTI ID:
- 5179691
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
LIGASES
ENZYME ACTIVITY
PHOSPHATES
HYDROLYSIS
ADP
ATP
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL HALF-LIFE
CHEMICAL BONDS
CLOSTRIDIUM
FOLIC ACID
NMR SPECTRA
OXYGEN 18
PHOSPHORUS 31
SUBSTRATES
WATER
AMINO ACIDS
AROMATICS
AZAARENES
BACTERIA
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DECOMPOSITION
DRUGS
ENZYMES
EVEN-EVEN NUCLEI
HEMATINICS
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPES
KINETICS
LIGHT NUCLEI
LYSIS
MICROORGANISMS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PTERIDINES
REACTION KINETICS
SOLVOLYSIS
SPECTRA
STABLE ISOTOPES
VITAMIN B GROUP
VITAMINS
550201* - Biochemistry- Tracer Techniques
550600 - Medicine