Abstract
Glycerol dehydrogenase catalyzes the reversible NAD+-dependent oxidation of glycerol to form dihydroxyacetone. Initial velocity, product, and dead-end inhibition studies performed for the forward and reverse reactions support an ordered kinetic mechanism with NAD+ binding first and NADH released last. A monovalent cation is required for enzymatic activity and glycerol binding, with K+ having the highest activity as measured by V. The pH dependence of the kinetic parameters V and V/Kglycerol, as well as the temperature dependence of the V pH profile, suggested that an enzymic carboxylate group functions as a base in catalysis. The pH dependence of the primary deuterium kinetic isotope effect shows that DV/kglycerol, increases from a pH-independent value of 1.15 at high pH values to a pH-independent value of 2.44 at low pH values. DV exhibits a similar pH dependence, increasing from a pH-independent value of 2.57 at high pH values to a pH independent value of 4.88 at low pH values. A chemical mechanism for enzymatic glycerol oxidation is proposed based on the data.
Original language | English (US) |
---|---|
Pages (from-to) | 14642-14649 |
Number of pages | 8 |
Journal | Biochemistry |
Volume | 33 |
Issue number | 48 |
DOIs | |
State | Published - Dec 1 1994 |
ASJC Scopus subject areas
- Biochemistry