소의 이하선 조직에서 세포질과 mitochondria 분획을 분리하고 세포질에 있는 $alpha$-glycerophosphate 탈수소효소($NAD^+$ 2-oxidoreductase, EC 1.1.1.8) 및 mitochondria에 있는 FAD 의존성 $alpha$-glycerophosphate 탈수소효소(cytochrome oxidoreductase, EC 1.1.99.5)의 분포를 관찰하였다. 이하선 조직 1 g당 세포질에 있는 NAD 의존성 효소의 활성도는 약 278 unit로 총활성도에 대하여 약 94%가 세포질에 함유되어 있었고 mitochondria에 있는 FAD 의존성 효소의 활성도는 약 16 unit로 총활성도에 대하여 약 44%가 mitochondria에 함유되어 있었다. NAD 의존성 및 FAD 의존성 효소에 의한 $alpha$-glycerophosphate의 산화 속도가 현저한 차이를 나타내는 점으로 보아 세포질과 mitochondria 구획 사이에서 $alpha$-glycerophosphate shuttle이 활발히 이루어지지 않는 것 같다. 부분 정제된 NAD 의존성 및 FAD 의존성 효소를 각각 DEAE-cellulose column chromatography를 하였을 때 두 효소 모두 효소의 활성이 있는 두개의 peak가 분리되는 점으로 보아 isozyme이 각각 존재하는 것으로 생각된다.
The distribution of NAD-linked $alpha$-glycerophosphate dehydrogenase ($NAD^+$ 2-oxidoreductase, EC 1.1.1.8) and FAD-linked $alpha$-glycerophosphate dehydrogenase (cytochrome oxidoreductase, EC 1.1.99.5) of bovine parotid gland have been studied. The activity of NAD-linked $alpha$-glycerophosphate dehydrogenase was found to be about 278 units per gram tissue and was recovered about 94% in cytosol. FAD-linked $alpha$-glycerophosphate dehydrogenase activity was about 16 units per gram tissue and the relative activity of mitochondrial fraction was 44%. The oxidation velocity by the NAD- and FAD-linked $alpha$-glycerophosphate dehydrogenase was strikingly differed between the cytosolic and mitochondrial fraction. This indicates that the $alpha$-glycerophosphate-dihydroxyacetone phosphate shuttle for the electron transport does not exist in the parotid gland of bovine. In order to identify the isozyme patterns of these enzymes, DEAE-cellulose colum chromatography was performed. The results of this column chromatography showed that these enzymes consist of two activity peaks. This suggests NAD- and FAD-linked $alpha$-glycerophosphate dehydrogenase of bovine parotid gland consist of several isozymes.
