Partial purification and some properties of øC2(W) lysin, a lytic enzyme produced by phage-infected cells ofStreptococcus lactisC2

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Abstract
SUMMARY: The lytic enzyme present in øC2(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 > 47°C. The apparent temperature optimum was 37°C and Q10and Eavalues over the range 22–32°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 ˜ 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 ofLeuconostoc, two species ofLactobacillus, one strain ofEscherichia coliand ofMicrococcus lysodeikticuswere apparently resistant. Analysis of cell wall degradation products gave results which were consistent with the lysin having the specificity of an N-acetylmuramidase.
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