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Ascaris suum muscle was fractionated by differential centrifugation into nuclear, mitochondrial and cytoplasmic fractions. The activity of mitochondrial FAD-linked α-glycerophosphate dehydrogenase(cytochrome oxidoreductase, EC 1.1.99.5) was determined by the procedure of Dowson and Thorne, and the activity of cytoplasmic NAD-linked α-glycerophosphate dehydrogenase(NAD 2-oxidoreductase, EC 1.1.1.8) was assayed according to the method of Gonzalez-Cerozo and Dalziel. Mitochondrial FAD-linked α-glycerophosphate dehydrogenase was purified by sodium deoxycholate solubilization and DEAE-cellulose column chromatography. The results obtained were as follows; 1. The distribution of FAD-linked α-glycerophospliate dehydrogenase in the subcellular organells showed that 62% of the activity was in mitochondrial, 29% in cytoplasmic and about 9% was in nuclear fraction. The specific activities were 1.26, 0.30, and 0.05, respectively. 2. The activity of FAD-linked α-glycerophosphate dehydrogenase in Ascaris suum muscle was 153.25 units/g. The specific activity of NAD-linked α-glycerophosphate dehydrogenase in cytosol was found to be about 2 fold greater than that of FAD-linked dehydrogenase in mitochondria. 3. It was demonstrated that there were two types of isozyme in the mitochondrial FAD-linked dehydrogenase, Enzyme Ⅰ and Enzyme Ⅱ. Enzyme Ⅰ and Ⅱ were purified about 87 and 854-fold increase in specific activities after chromatography on DEAE-cellulose. 4. The specific activity of Enzyme Ⅱ was found 9.8 times as high as Enzyme Ⅰ, and Enzyme Ⅰ and Ⅱ were contained 87.7% and 12.3% respectively. 5. The optimal temperature of Enzyme Ⅰ and Ⅱ were 35℃ and the optimal pH of Enzyme Ⅰ and Ⅱ were 7.6. 6. The Km values for α-glycerophosphate of Enzyme Ⅰ and Ⅱ were 2.33 mM and 0.82 mM, respectively.
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