Mullan W M, Crawford R J
J Dairy Res. 1985 Feb;52(1):123-38. doi: 10.1017/s0022029900023955.
The lytic enzyme present in phi C2(W) lysates was isolated by means of ion-exchange chromatography and further purified by gel filtration and ultrafiltration. The phage enzyme had an apparent pH optimum of 6.5-6.9 and was rapidly inactivated at temperatures greater than 47 degrees C. The apparent temperature optimum was 37 degrees C and Q10 and Ea values over the range 22-32 degrees C were 2.5 and 69.2 kJ/mol respectively. Monovalent and divalent cations activated the enzyme. Reduced -SH groups on the enzyme were required for lytic activity. Gel filtration revealed a mol. wt of approximately 46000. Strain-dependent differences in sensitivity of group N lactic streptococci to lysin were found. Group D streptococci were also lysed. Strains of three species of Leuconostoc, two species of Lactobacillus, one strain of Escherichia coli and of Micrococcus lysodeikticus were apparently resistant. Analysis of cell wall degradation products gave results which were consistent with the lysin having the specificity of an N-acetylmuramidase.
通过离子交换色谱法分离出存在于φC2(W)裂解物中的裂解酶，并通过凝胶过滤和超滤进一步纯化。该噬菌体酶的表观最适pH为6.5 - 6.9，在高于47℃的温度下迅速失活。表观最适温度为37℃，在22 - 32℃范围内的Q10和Ea值分别为2.5和69.2 kJ/mol。单价和二价阳离子可激活该酶。酶的裂解活性需要还原型 -SH基团。凝胶过滤显示分子量约为46000。发现N群乳酸链球菌对溶菌素的敏感性存在菌株依赖性差异。D群链球菌也会被裂解。三种明串珠菌属、两种乳杆菌属、一株大肠杆菌和溶壁微球菌的菌株显然具有抗性。细胞壁降解产物的分析结果与该溶菌素具有N - 乙酰胞壁酸酶的特异性一致。
