NAD+/NADP+-Dependent Malic Enzyme: Evidence of a NADP+ Preferring Activity in Human Skeletal Muscle

The L-malate NAD(P)+ oxidoreductase (decarboxylating) E.C.1.1.1.39 was purified from human skeletal muscle; the specific activity estimated in the presence of NADP+ as coenzyme was ∼15 μmol/min/mg. The apparent Vmax values for NAD+ (∼8 μmol/min/mg) and NADP+ (∼16 μmol/min/mg) show that the enzyme (i...

Full description

Saved in:

Bibliographic Details
Published in:	Biochemical and molecular medicine 1995-10, Vol.56 (1), p.14-18
Main Authors:	Liguori, M., Tessarolo, D., Abbruzzese, C., Giacanelli, M.
Format:	Article
Language:	eng
Subjects:	Carboxy-Lyases - metabolism Chromatography, Affinity Chromatography, Ion Exchange Electrophoresis, Polyacrylamide Gel Humans Hydrogen-Ion Concentration Kinetics Malate Dehydrogenase - isolation & purification Malate Dehydrogenase - metabolism Muscle, Skeletal - enzymology NAD - metabolism NADP - metabolism Pyruvate Carboxylase - metabolism
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	The L-malate NAD(P)+ oxidoreductase (decarboxylating) E.C.1.1.1.39 was purified from human skeletal muscle; the specific activity estimated in the presence of NADP+ as coenzyme was ∼15 μmol/min/mg. The apparent Vmax values for NAD+ (∼8 μmol/min/mg) and NADP+ (∼16 μmol/min/mg) show that the enzyme (in this tissue) is more active in the presence of NADP+. This observation was confirmed by the estimation of enzymatic activity in competition experiments where both NAD+ and NADP+ were used together as coenzymes. The absence of pyruvate carboxylation and of oxalacetate decarboxylation activities demonstrates that the enzyme studied is E.C.1.1.1.39. In addition, the apparent Km values for NAD+ and NADP+ were calculated (15 and 0.05 mM, respectively). This paper provides the first demonstration of a NADP+ preferring activity of the enzyme in human skeletal muscle.
ISSN:	1077-3150 1095-5577