Kühnlein U, Linn S, Arber W
Proc Natl Acad Sci U S A. 1969 Jun;63(2):556-62. doi: 10.1073/pnas.63.2.556.
An enzymatic activity, having the properties expected of a B-specific host-controlled modification enzyme, has been purified from an extract of Escherichia coli strain B. This activity renders the unmodified replicative form of phage fd resistant to B-specific restriction and is only present in strains carrying intact genes for type B modification. In phosphate buffer, the enzyme acts optimally at pH 6 and is dependent upon a single cofactor, S-adenosylmethionine.
已从大肠杆菌B菌株提取物中纯化出一种具有B特异性宿主控制修饰酶预期特性的酶活性。这种活性使噬菌体fd的未修饰复制型对B特异性限制具有抗性,并且仅存在于携带完整B型修饰基因的菌株中。在磷酸盐缓冲液中,该酶在pH 6时作用最佳,并且依赖于单一辅因子S-腺苷甲硫氨酸。