猪胰脏羧肽酶转酯功能和耐酸抗蛋白酶特性研究

摘要

羧肽酶（carboxypeptidase）是一类可水解肽链C末端氨基酸残基的蛋白酶，可用作饲料添加剂，促进畜禽生长。猪胰脏中含有一种羧肽酶A1（CPA1），该酶除能水解蛋白质外，还能分解油脂。CPA1在以酪蛋白和橄榄油为底物时，比活力分别为53.14 U/mg和22.4 U/mg；经过pH2.0酸性环境和胰蛋白酶处理后，其酶活残留率分别为95.65%和78.14%。结果表明，CPA1具有转酯功能和耐酸抗蛋白酶特性。%Carboxypeptidase is a kind of protease that cleaves the peptide bond of an amino acid residue at the C-terminal end. It can be used in feed additives, and promotes the growth of livestock and poultry. A carboxypeptidase A1(CPA1)was obtained from porcine pancreas, and it can hydrolyze proteins and decompose oils. It showed the specific activity as 53.14 U/mg and 22.4 U/mg when casein and olive oil used as substrate, respectively. The CPA1’s relative activity reached 95.65% and 78.14% respectively after the treatment of pH2.0 acidic and trypsin. The results indicate that the CPA1 has the function of transesterification and the feature of distinct acid-resistant antiprotease.