1987 年 101 巻 3 号 p. 619-624
Carboxylesterase [EC 3. 1. 1. 1] was purified from rabbit liver lysosomes by means of detergent solubilization, and by hydroxyapatite, phenyl-Sepharose and chromatofocusing column chromatographies. The purified enzyme appeared to be homogeneous on SDS-polyacrylamide gel electrophoresis and its molecular weight was estimated to be 58, 000. This enzyme was eluted at an isoelectric point of approximately 5.8 by chromatofocusing, and exhibited a broad pH optimum of between 6.0 and 9.0. The enzyme hydrolyzed 4-methylumbelliferyl esters of saturated fatty acids (C2-C12), and it also hydrolyzed p-nitrophenylacetate, methyl butyrate, and tributyrin, but not acetanilide. Its activity was completely inhibited by diisopropylfluorophosphate (DFP) and phenylmethylsulfonyl fluoride (PMSF) at 10-4M, but was not affected by eserine, or by α- or β-naphthyl acetate at 10-3M. Various metal ions (Mg2+, Mn2+, Ca2+, Co2+, Cu2+, Zn2+, Ni2+) at 10-3M also had no effect on the enzyme activity.