Abstract
The enzyme malate dehydrogenase (MDH) is known to exist in two distinct forms in most mammalian tissues. One is present in the cytoplasm as a soluble enzyme (S-MDH), and the other is bound to the mitochondria (M-MDH). Among the distinct physical and chemical properties of these two enzymes are the different patterns seen after starch gel electrophoresis and specific enzymatic staining (see diagram: usual). Recent studies have suggested that the usual minor mitochondrial bands (1–4) are conformational modifications of a single protein, band 5. We have previously reported a rare genetic variant of soluble MDH found in the red cells of one apparently normal Negro female out of 3000 individuals examined. This report concerns a new inherited electrophoretic variant of M-MDH found in either leukocyte or placental extract of 3 of 350 unselected normal individuals. The electrophoretic pattern of this variant is shown in the diagram. The two additional major bands of MDH activity have identical electrophoretic mobility with minor bands 4 and 3 of the normal mitochondrial pattern. Family studies of two of the probands show that affected individuals are heterozygous for a relatively common autosomal mutant gene. All of the individuals found to have the mitochondrial variant have normal S-MDH patterns, adding further evidence that the two intracellular forms of MDH are under the control of different genes. (SPR)
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Cortner, J., Davidson, R. & Rubin, M. 21 A Genetic Variant of Human Mitochondrial Malate Dehydrogenase. Pediatr Res 1, 205–206 (1967). https://doi.org/10.1203/00006450-196705000-00028
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DOI: https://doi.org/10.1203/00006450-196705000-00028