우리나라産 메기(Parasilurus asotus)의 내장에 존재하는 L-Ornithine aminotransferase 에 관한 연구

Abstract

우리나라산 담수어인 메기(Parasilurus asotus)의 내장중에 존재하는 ornithine aminotransferase의 활성도를 측정하여 enzyme의 분포와 그 물리화학적 성질을 연구하였다. 그 결과는 다음과 같다. 1. 메기의 각 내장을 cel1 fractionation하여 enzyme activity를 측정하였더니 ornithine aminotransferase는 mitochondrial fraction에 60~70%, cytosol fraction에 10~30%가 들어있었으며, 내장 부위에 대한 homogenate의 activity를 비교하여 보면, 간의 경우 3.639 units/g tissue로 가장 크며 간〉심장〉신장〉쓸개〉지라〉정소〉난소의 순이었다. 2. Ammonium sulfate fractionation에 의해 부분 정제된 enzyme의 optimum pH는 7.2이었으며, isoelectric point는 5.5~5.6이었다. 그리고 Michaelis constant는 L-ornithine에 대해 4.67 mM, α-ketoglutaric acid에 대해 0.486mM이었다.;The activity of ornithine aminotransferase was measured in internal organs of Korean Parasilurus asotus. The distribution of the enzyme in various organs and physicochemical properties of the partially purified liver enzyme were studied. The results are as follows. 1. As the activity of the enzyme was measured in internal organs by means of the cell fractionation, the 60-70% of the enzyme had been contained in its' mitochondria1 fraction and the 10-30% had been contained in its' cytosol fraction. The relative activity of the enzyme in internal organs was found to be; Liver>Heart>Kidney>Bile>Spleen>Testes>Ovaries. The organ activities ranged from 3.639 units/g tissue (liver) to 0.093 units/g tissue (Ovaries). 2. The pH optimum of the partially purified liver enzyme by means of ammonium sulfate fractionation was found to be approx. 7.2, and the isoelectric point was found to be between 5.5 and 5.6. The Michaelis constants (Km's) for L-ornithine and α-keto-gulutaric acid were 4.67 mM and 0.486 mM respectively.