, PODRAVKA, I. Marinkovića 32, 43300, Koprivnica, Yugoslavia.
World J Microbiol Biotechnol. 1990 Jun;6(2):195-200. doi: 10.1007/BF01200941.
Urease (urea amidohydrolase E.C.3.5.1.5) synthesis inMicrococcus varians U-9 was not affected by nitrogen source (peptone or glutamic acid) or its concentration: but depended on the ratio of peptone and urea in culture medium. WhenM. varians grew in culture medium with peptone at or above 0.48g/l and NH4Cl as an additional nitrogen source, two maxima of urease synthesis occurred; one in the exponential growth phase and the second in the stationary growth phase. Though this bacterium could not utilize either urea or ammonia as the sole nitrogen source, urea caused only one maximum of urease synthesis to occur and shifted the maximum into late exponential phase, suggesting that urea acts as a regulatory factor in urease synthesis. Synthesis of urease was not induced either by urea or by nitrogen starvation and was not repressed by ammonia or by excess of complex nitrogen source. NI(2+) (up to 0.1 mM) stimulated urease synthesis but decreased bacterial growth, while Co(2+) only affected bacterial growth and at 0.1 mM Inhibited the growth.
粘球菌 U-9 的脲酶（尿素酰胺水解酶 EC3.5.1.5）合成不受氮源（蛋白胨或谷氨酸）或其浓度的影响：但取决于培养基中蛋白胨和尿素的比例。当 M. varians 在含有蛋白胨的培养基中生长，且蛋白胨浓度为 0.48g/l 或以上，并且 NH4Cl 作为额外的氮源时，脲酶合成会出现两个最大值：一个在指数生长阶段，另一个在静止生长阶段。尽管这种细菌不能将尿素或氨用作唯一氮源，但尿素只会导致一次脲酶合成的最大值出现，并将最大值转移到指数后期，这表明尿素在脲酶合成中起调节因子的作用。脲酶的合成既不受尿素也不受氮饥饿的诱导，也不受氨或过量复杂氮源的抑制。NI(2+)（高达 0.1mM）刺激脲酶合成，但会降低细菌生长速度，而 Co(2+) 仅影响细菌生长速度，且在 0.1mM 时会抑制生长。
