Prusiner S
J Bacteriol. 1975 Sep;123(3):992-9. doi: 10.1128/jb.123.3.992-999.1975.
Nitrogenous metabolites, cyclic adenosine 3':5'-monophosphate (cAMP), and the stage of culture growth all influence the levels of glutaminase A in Escherichia coli, but no variables in culture conditions alter the levels of glutaminase B. Growth of E. coli on culture media containing glucose and excess ammonia results in a rise in the level of glutaminase A as the cultures enter stationary phase; this rise is abolished by ammonia limitation. cAMP or glycerol reduce the level of glutaminase A. In mutants deficient in cAMP receptor protein, glutaminase A levels are unchanged by cAMP, but they are still susceptible to regulation by ammonia. We consider glutaminase B to be a constitutive enzyme, since its levels appear independent of nutritional conditions.
含氮代谢物、环磷酸腺苷（cAMP）以及培养生长阶段均会影响大肠杆菌中谷氨酰胺酶A的水平，但培养条件中的任何变量都不会改变谷氨酰胺酶B的水平。大肠杆菌在含有葡萄糖和过量氨的培养基上生长时，随着培养物进入稳定期，谷氨酰胺酶A的水平会升高；氨限制会消除这种升高。cAMP或甘油会降低谷氨酰胺酶A的水平。在缺乏cAMP受体蛋白的突变体中，cAMP不会改变谷氨酰胺酶A的水平，但它们仍易受氨的调节。我们认为谷氨酰胺酶B是一种组成型酶，因为其水平似乎与营养条件无关。
