Carbon-13 and deuterium isotope effects on the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase

Journal Article · Tue Sep 10 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00100a021· OSTI ID:5821279

Canellas, P F; Cleland, W W ^[1]

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1. Univ. of Wisconsin, Madison (United States)

Carbon-13 and deuterium isotope effects have been measured on the reaction catalyzed by rabbit muscle glyceraldehyde-3-phosphate dehydrogenase in an effort to locate the rate-limiting steps. With D-glyceraldehyde 3-phosphate as substrate, hydride transfer is a major, but not the only, slow step prior to release of the first product, and the intrinsic primary deuterium and {sup 13}C isotope effects on this step are 5-5.5 and 1.034-1.040, and the sum of the commitments to catalysis is {approximately} 3. The {sup 13}C isotope effects on thiohemiacetal formation and thioester phosphorolysis are 1.005 or less. With D-glyceraldehyde as substrate, the isotope effects are similar, but the sum of commitments is {approximately} 1.5, so that hydride transfer is more, but still not solely, rate limiting for this slow substrate. The observed {sup 13}C and deuterium equilibrium isotope effects on the overall reaction from the hydrated aldehyde are 0.995 and 1.145, while the {sup 13}C equilibrium isotope effect for conversion of a thiohemiacetal to a thioester is 0.994, and that for conversion of a thioester to an acyl phosphate is 0.997. Somewhat uncertain values for the {sup 13}C equilibrium isotope effects on aldehyde dehydration and formation of a thiohemiacetal are 1.003 and 1.004.

• OSTI ID: 5821279
• Journal Information: Biochemistry; (United States), Vol. 30:36; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CARBON 13
ISOTOPE EFFECTS
DEUTERIUM COMPOUNDS
HEMIACETAL DEHYDROGENASES
BIOCHEMICAL REACTION KINETICS
ISOTOPE RATIO
MUSCLES
RABBITS
ANIMALS
CARBON ISOTOPES
ENZYMES
EVEN-ODD NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAMMALS
NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTEINS
REACTION KINETICS
STABLE ISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques