Effect of L-malate on pyruvate dehydrogenase activity of spermatozoa.
Presence of L-malate (from 0.5 to 4 mM concentrations) in the medium produces a marked increment of pyruvate consumption by the special type of mitochondria found in the middle piece of spermatozoa (sperm-type mitochondria, STM). Pyruvate uptake by liver mitochondria is not increased by malate. A comparative study on pyruvate dehydrogenase (PDH) of STM and liver mitochondria from mouse, rat, and rabbit showed that 2 mM L-malate does not modify significantly the activity of liver PDH, while it increases markedly that of spermatozoal PDH in the three species. The differential sensitivity to L-malate appears to be a peculiar regulatory property of the PDH complex in the gametes, which contains at least one component (E1, pyruvate decarboxylase, EC 1.2.4.1) known to be a sperm-specific isozyme.
Gerez de Burgos
N M
NM
Cátedra de Quimica Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
Gallina
F
F
Burgos
C
C
Blanco
A
A
D000818:Animals; D007700:Kinetics; D007773:Lactates / Q000378:metabolism; D008293:Malates / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009928:Organ Specificity; D010084:Oxidation-Reduction; D011767:Pyruvate Decarboxylase / Q000378:metabolism; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D013094:Spermatozoa / Q000201:enzymology*
D007773:Lactates; D008293:Malates; D011768:Pyruvate Dehydrogenase Complex; D011773:Pyruvates; D009243:NAD; C030298:malic acid; D011767:Pyruvate Decarboxylase