사람 태반의 branched chain amino산 amino기 전위 효소에 관하여 관찰하였다. 이 효소는 세포질과 mitochondria에서 발견되며 세포질에 약 70~80%, mitochondnia에 8~15%가 분포되어 있으며 나머지 약간량이 핵분획에 들어 있다. 이 효소의 태반속의 활성도는 다른 조직 즉 흰쥐의 장, 취장 및 심장 등에 비하여 낮다. 이 효소는 세포질 속에서 2종의 isozyme 즉 Enzyme I과 Enzyme III이 발견되며 Enzyme I은 DEAE-cellulose column chromatography에서 인산염 완충액 0.02M에서 Enzyme III은 0.2M에서 각각 용출되며 Enzyme I은 활성도가 Enzyme III의 활성도보다 훨씬 높다.
A study was undertaken on the distribution of branched chain amino acid aminotransferase (EC 2.6.1.6) in human placenta. This enzyme is localized in both the cytosolic and mitochondrial fraction. About 70~80 per cent of the total activity was found in the cytosolic fraction, 8~15 per cent in the mitochondrial fraction. In the human placenta the aminotransferase activities for branched chain amino acids are relatively low compared with those in rat tissues, i. e., intestine, pancreas, and heart. The present studies demonstrated that there are tow types of isozyme in the cytosolic fraction, Enzyme I and Enzyme III. Enzyme I was eluted by 0.02M phophate buffer from DEAE cellulose column and catalyzed the transamination of all three branched chain amino acids. Enzyme IQ was eluted by 0.2M buffer. It was found that the cytosolic fraction of human placenta contained much more Enzyme I than Enzyme III.
