| Abstrakt: |
Tween 80‐hydrolyzing esterases produced by various species of rapidly growing mycobacteria were partially purified from sonicated cell lysates by diethylaminoethyl (DEAE) cellulose and subsequent Sephadex G‐150 column chromatographies. The amount of the esterase produced per gram of bacterial cells varied markedly with each species. Mycobacterium smegmatis, M. chelonei, and M. phleiwere high producers and M. chitaeand M. diernhoferiwere low producers of Tween‐hydrolyzing esterase. The resistance of each mycobacterial strain to oleic acid correlated well with their esterase‐producing ability. All the esterases studied were adsorbed on DEAE cellulose in 50 mM Tris‐HCl buffer (pH 7.5), indicating that they are acidic proteins. Esterases of M. smegmatis, M. chitae, M. fortuitum, and M. phleiwere eluted from DEAE at high concentrations (0.11–0.18 m) of ammonium sulfate, while those of M. parafortuitumand M. diernhoferiwere eluted at lower concentrations (0.05–0.08 m). With Sephadex G‐150 gel filtration, all esterases were shown to have similar molecular weights (36,000 to 58,000). On the basis of heat‐stability and trypsin‐ or chymotrypsin‐sensitivity, these esterases were divided into three groups: one was heat‐stable and protease‐sensitive (M. smegmatisand M. fotuitum), another was heat‐labile and protease‐resistant (M. chelonei), and the other was the intermediate of the above two groups (M. diernhoferi). |
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