Suzuki J, Katoh N
Yamagata Mogami Livestock Hygiene Service Center, Japan.
Nihon Juigaku Zasshi. 1990 Oct;52(5):947-54. doi: 10.1292/jvms1939.52.947.
Cysteine protease was found to be present in bovine milk that catalyzed casein as the substrate. The protease was activated by reducing agents such as 2-mercaptoethanol and inhibited by monoiodoacetic acid, but not affected by the addition of phenylmethylsulfonyl fluoride, calcium or ethylene glycol bis (beta-aminoethyl)-N,N,N',N'-tetraacetic acid. The protease activity was linear as a function of protein amount and incubation time, and showed maximum at pH 6.0. By Sephacryl S-200 chromatography, at least two types of cysteine proteases having molecular weights of 45 kDa and more than 150 kDa were detected. The activity was increased in mastitic milk, and well correlated with the stages of mastitis, as indicated by the California mastitis test, somatic cell count and protein concentration. These results suggested that cysteine protease(s) is involved in the pathogenesis of mastitis.
发现半胱氨酸蛋白酶存在于牛乳中，它以酪蛋白为底物进行催化。该蛋白酶可被诸如2-巯基乙醇等还原剂激活，被单碘乙酸抑制，但不受苯甲基磺酰氟、钙或乙二醇双（β-氨基乙基）-N,N,N',N'-四乙酸添加的影响。蛋白酶活性与蛋白量和孵育时间呈线性关系，在pH 6.0时显示出最大值。通过Sephacryl S-200色谱法，检测到至少两种分子量分别为45 kDa和超过150 kDa的半胱氨酸蛋白酶。如加利福尼亚乳房炎检测、体细胞计数和蛋白质浓度所示，该活性在患乳房炎的乳中增加，且与乳房炎的阶段密切相关。这些结果表明半胱氨酸蛋白酶参与了乳房炎的发病机制。
