title: Factors influencing the synthesis of an extracellular proteinase by Enterococcus faecalis subsp. liquefaciens.
abstract: Studies were conducted on optimum temperature, pH and the requirement for an energy source, amino acids, casein, Zn2+ and Ca2+ during the synthesis of an extracellular acid proteinase by Enterococcus faecalis var. liquefaciens. Synthesis was monitored using cells grown to mid-logarithmic phase and resuspended at high density in fresh growth medium. Proteinase production was optimal at 30 degrees C and pH 7.0. Proteinase synthesis, being energy-dependent, occurred only in glycolysing cells. The synthesis was high when lactose but not glucose was utilized as a source of energy, indicating that phospho-beta-galactosidase gene might probably be located directly upstream the proteinase gene on a plasmid. Good induction of proteinase synthesis could be achieved by 0.2-0.5% of either yeast extract or tryptic digested casein, perhaps due to its content of a wide variety of free amino acids. Casein was essential for preventing proteinase autolysis and sustaining the enzyme production. Zn2+ and Ca2+ were required for the formation of an active extracellular proteinase. The synthesis immediately ceased after addition of chloramphenicol or EDTA. EDTA inactivated the preformed proteinase as well. Sodium chloride at a concentration of 6.5% inhibited both proteinase synthesis and glycolysis.
authors.affiliation: Dairy Department, Faculty of Agriculture, University of Assiut, Egypt.
authors.forename: F Z
authors.initials: FZ
authors.lastname: Hegazi
mesh_terms: D002364:Caseins / Q000494:pharmacology; D002701:Chloramphenicol / Q000494:pharmacology; D003470:Culture Media; D010450:Endopeptidases / Q000096:biosynthesis*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature
chemical_list: D002364:Caseins; D003470:Culture Media; D012965:Sodium Chloride; D002701:Chloramphenicol; D010450:Endopeptidases