Effect of inhibitors of trypsin-like proteolytic enzymes Bacillus cereus T spore germination.
The germination of Bacillus cereus T spore suspensions is partially prevented by several inhibitors of trypsin-like enzymes. Leupeptin, antipain, and tosyl-lysine-chloromethyl ketone are effective inhibitors, whereas chymostatin, elastatinal, and pepstatin are inactive. A synthetic substrate of trypsin, tosyl-arginine-methyl ester, also inhibits germination. Its inhibitory effect decreases as a function of incubation time in the presence of spores and is abolished by previous hydrolysis with trypsin. Germinating, but not dormant, spore suspensions hydrolyze tosyl-arginine-methyl ester; its hydrolysis is insensitive to chloramphenicol, sulfhydryl reagents, and EDTA. A crude extract of germinated B. cereus spores contains a trypsin-like enzyme whose activity, as measured by hydrolysis of benzoyl-arginine p-nitroanilide, is sensitive to germination-inhibitory compounds such as leupeptin, tosyl-arginine-methyl ester, and tosyl-lysine-chloromethyl ketone. Spore suspensions exposed to the above inhibitors under germination conditions lose only part of their heat resistance and some 10 to 30% of their dipicolinic acid content. Part of the germinating spore population becomes "phase grey" under phase optics. Based on a study of the inhibition of germination by protease inhibitors and the activity of a protease in germination spores and spore extracts, it is suggested that the activity of a trypsin-like enzyme may be involved in the mechanism of the breaking of dormancy in spores of B. cereus T.
D000976:Antipain / Q000494:pharmacology; D001409:Bacillus cereus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D007976:Leupeptins / Q000494:pharmacology; D013171:Spores, Bacterial / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D014106:Tosylarginine Methyl Ester / Q000494:pharmacology; D014107:Tosyllysine Chloromethyl Ketone / Q000494:pharmacology; D014357:Trypsin / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000494:pharmacology*
D007976:Leupeptins; D014361:Trypsin Inhibitors; D014107:Tosyllysine Chloromethyl Ketone; D000976:Antipain; D014106:Tosylarginine Methyl Ester; D014357:Trypsin