biologia plantarum

Biologia plantarum 44:535-539, 2001 | DOI: 10.1023/A:1013786518950

Purification and Kinetic Characterisation of Lactate Dehydrogenase from Dioscorea cayenensis Tuber

U. Oluoha¹

¹ Department of Biochemistry, Faculty of Science, University of Benin, Benin, Nigeria

Lactate dehydrogenase from yellow yam tuber (Dioscorea cayenensis Lam.) was isolated and purified using various chromatographic methods and electrophoresis. Only one form of the enzyme obtained, which obeyed Michaelis-Menten kinetics, was activated by Mg²⁺ and Ca²⁺ and inhibited by nucleotides and PEP. AMP, which activated the enzyme in the direction of pyruvate reduction, inhibited it in the direction of lactate oxidation. The enzyme is specific for pyruvate L-lactate and uses only NADH and NAD⁺ as the electron carriers. Polyacrylamide gel electrophoresis showed single band of lactate dehydrogenase activity. The average molecular mass obtained for the enzyme was 160 ± 1.2 kDa, while SDS gel electrophoresis indicated a dimer for the enzyme protein. The enzyme is very stable when frozen but its activity was hardly detectable when the tubers were stored in a well aerated place.

Keywords: L-lactate; pyruvate; SDS gel electrophoresis; yam

Subjects: Dioscorea cayenensis; lactate dehydrogenase, purification, chromatography, electrophoresis; lactate dehydrogenase; tuber, yam, lactate dehydrogenase; yam

Published: December 1, 2001  Show citation