Induction and carbon catabolite repression in the biosynthesis of beta-amylase by Bacillus megaterium B6.
Biosynthesis of extracellular beta-amylase in Bacillus megaterium B6 was induced by starch, although maltodextrin was found to be the actual inducer. Amongst the carbon sources tested, glucose was found to be the most potent repressor and when added exogenously to a starch-induced culture it brought about an immediate fall in enzyme synthesis through carbon catabolite repression. The repression was not overcome after the fall of glucose concentration in the culture medium below a critical level. This "catabolite repression" exerted by glucose was partially relieved by exogenous cyclic guanosine monophosphate (CGMP) and its dibutyryl derivative. On the other hand, guanosine monophosphate (GMP) was found to restore the original extent of enzyme synthesis in glucose repressed cells.
Ray
R R
RR
Department of Microbiology, Bose Institute, Calcutta, India.
Jana
S C
SC
Nanda
G
G
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001410:Bacillus megaterium / Q000201:enzymology* / Q000254:growth & development; D002244:Carbon / Q000378:metabolism*; D006152:Cyclic GMP / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004794:Enzyme Repression / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006157:Guanosine Monophosphate / Q000494:pharmacology; D007700:Kinetics; D011134:Polysaccharides / Q000494:pharmacology; D013213:Starch / Q000494:pharmacology; D001614:beta-Amylase / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D011134:Polysaccharides; D002244:Carbon; C008315:maltodextrin; D006157:Guanosine Monophosphate; D013213:Starch; D001614:beta-Amylase; D006152:Cyclic GMP; D005947:Glucose