Eremenko V V, Zhukov A V, Nikolaev A Ia
Mikrobiologiia. 1975 Jul-Aug;44(4):615-20.
The cells of Pseudomonas fluorescens AG contain two inducable asparaginase enzymes: one of them hydrolyzes only L-asparagine (asparaginase A), the other--L-asparagine, L-glutamine, and D-asparagine (asparaginase AG). In the conditions of continuous cultivation of the bacteria, aspartic and glutamic acids induce the formation of these enzymes only when the amino acids were used simultaneously as a growth-limiting factor and as a sole source of carbon and nitrogen. Both enzymes are not induced in the conditions when the growth is limited by the nitrogen of these amino acids. When the growth was limited by carbon, asparagine, aspartic and glutamic acids induce asparaginase AG more than asparaginase A. Asparagine and glutamine are better inductors than the corresponding amino acids. The activity of asparaginase and glutaminase increases with the specific growth rate of the culture. The induced synthesis of both amidases, after prolonged growth of the culture on a defined medium with glycerol, is inhibited by glycerol but not by glucose. The results are discussed from the viewpoint of regulation of amidases in these bacterial cells.
荧光假单胞菌AG的细胞含有两种可诱导的天冬酰胺酶:其中一种仅水解L-天冬酰胺(天冬酰胺酶A),另一种水解L-天冬酰胺、L-谷氨酰胺和D-天冬酰胺(天冬酰胺酶AG)。在细菌连续培养的条件下,只有当氨基酸同时作为生长限制因子以及碳和氮的唯一来源时,天冬氨酸和谷氨酸才会诱导这些酶的形成。当生长受这些氨基酸的氮限制时,两种酶均不会被诱导。当生长受碳限制时,天冬酰胺、天冬氨酸和谷氨酸对天冬酰胺酶AG的诱导作用比对天冬酰胺酶A的诱导作用更强。天冬酰胺和谷氨酰胺比相应的氨基酸是更好的诱导剂。天冬酰胺酶和谷氨酰胺酶的活性随培养物的比生长速率增加。在含有甘油的限定培养基上长时间培养后,两种酰胺酶的诱导合成受到甘油的抑制,但不受葡萄糖的抑制。从这些细菌细胞中酰胺酶的调节角度对结果进行了讨论。