Malate dehydrogenase molecular weight

Fieldes, M. A., and Dixon, B., 1988, Malate dehydrogenase isozymes in flax genotroph leaves differences in apparent molecular weight and charge between and within L and S, Biochem. Genet. 26 249-260. 

GDH, GS, and malate dehydrogenase (MDH) activities have been also studied in carrot cells suspensions (Muscolo et al., 1999). All enzymes tested were positively affected by the humic fraction with low molecular weight. The activities of GDH,... 

The reported values for the molecular weight of the malate dehydrogenase isozymes from mammalian sources have varied over the range of 15,000-74,000 including many intermediate values. However, more recent reports have placed the values for both enzymes consistently in the... 

N. crassa m-, and E. coli. In each case, identical elution positions were observed corresponding to a molecular weight of 67,000. This study eliminates the possibility that the mitochondrial and cytoplasmic isozymes vary markedly in size. In addition. X-ray diffraction studies (57) and amino acid sequence analysis (55) have clearly established that the cytoplasmic form of pig heart malate dehydrogenase to be about 72,000. Sequence (55) and compositional analyses i/fi) of the mitochondrial en-... 

Mitochondrial malate dehydrogenase (MDH) from several species has been shown to exist in several enzymically active forms which also appear to be conformational isoenzymes (Kitto et al, 1966, 1970). Kitto et al (1970) showed, in contrast to Epstein and Schechter (1968), that these MDH s were interconvertible in vitro, had the same amino acid compositions and molecular weights, but differed, once reversibly denatured, considerably in their heat stability. Similar interconversion of isoenzymes has also been observed with purified preparations of horse liver alcohol dehydrogenase (Lutstorf and von Wartburg, 1969). The question arises if such conformers are of any physiological or functional significance. It is possible that beeause of their differences in surface charge, the various conformative isoenzymes are differently bound within a cell. 

The molecular weight of the malate dehydrogenase dimer is 70000, and this represents the largest unit determined at high resolution by Z-ray analysis to date. 

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