Influence of vanadate on the various activities of mammalian phosphoglycerate mutase: kinetic studies and mechanistic implications

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5145396

Stankiewicz, P J; Hass, L F

Recent NMR studies indicate that vanadium (V) forms coordinate-covalent complexes with aliphatic alcohols. Similarly, kinetic measurements suggest that metavanadate (VO/sub 3//sup -/) reacts with the free OH-group of glycerate-3-P (3-PGA) to form a binary complex which strongly competes with glycerate-2,3-P/sub 2/ (2,3-DPG) for the active site of rabbit muscle phosphoglycerate mutase (PGM). Thus, short-term pre-incubation of PGM with VO/sub 3//sup -/ and 3-PGA followed by 2,3-DPG addition yields an initial lag which gradually develops into an inhibited steady-state reaction velocity. Any other combination of pre-incubation components manifests uninhibited initial velocities which ultimately diminish to inhibited steady-state levels. At constant VO/sub 3//sup -/ concentrations, inhibition increases to a limiting value as a function of 3-PGA (or 2-PGA) concentration. A replot of slope vs. 3-PGA from reciprocal plots (1/v vs. 1/2,3-DPG) at constant VO/sub 3//sup -/ yields an apparent K/sub eg/ of 630 M/sup -1/ for the equilibrium: VO/sub 3/ + 3-PGA = 2-V-3-PGA + E = E x 2-V-3-PGA. 2,3-DPG phosphatase activity of PGM is sigmoidally activated as a function of VO/sub 3//sup -/ concentration. A Hill plot for vanadate activation yields a value of n=2.0, suggesting maximal subunit cooperativity. Half maximal activation occurs at 0.31 mM vanadate.

• Research Organization: Penn State Univ., Hershey
• OSTI ID: 5145396
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560301* -- Chemicals Metabolism & Toxicology-- Cells-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
ENZYME ACTIVITY
ENZYMES
INHIBITION
KINETICS
MAMMALS
MUSCLES
OXYGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
RABBITS
REACTION KINETICS
TRANSFERASES
TRANSITION ELEMENT COMPOUNDS
VANADATES
VANADIUM COMPOUNDS
VERTEBRATES