Jyssum S
Kaptein W. Wilhelmsen og Frues Bakteriologiske Institutt, University of Oslo, Rikshospitalet, Norway.
APMIS. 1992 Jan;100(1):48-56.
The regulatory characteristics of aspartate carbamoyltransferase (ACTase EC 2.1.3.2) from various species of Neisseria and Branhamella have been compared. Great differences in the regulatory nature of the enzymes were observed. ATP and GTP were positive effectors in Neisseria meningitidis, N. gonorrhoeae and nine other coccal "true neisseriae" species. In four "false neisseriae" species, including Branhamella catarrhalis, no stimulating effect of ATP or GTP was observed. The rod-shaped N. elongata behaved as the "false neisseriae" in these respects, despite its taxonomic affinity to the coccal "true neisseriae" species. Except in N. meningitidis and N. lactamica, CTP had no distinct stimulatory effect. CTP had a strong inhibitory effect on ACTases from N. elongata and the "false neisseriae" species N. caviae and B. catarrhalis. The inhibitory effect of CTP was weak in N. cinerea, N. denitrificans, and the "false neisseriae" species N. ovis and N. cuniculi. Thus, there was no sharp reflection of taxonomy in the regulation of ACTase by CTP in these groups of bacteria. The apparent [S]0.5 values for aspartate and carbamoyl phosphate, displayed for five of the eighteen species, showed great variability with [S]0.5 values for aspartate ranging from 6 to 34, and for carbamoyl phosphate from 2 to 9. Treatment of the enzyme from the main test microbe N. meningitidis strain M1 by heat or para-chloromercuribenzoate (pCMB) showed that both the catalytic and the regulatory functions decreased in parallel as in the class A enzymes found in species of Pseudomonas. An estimation of the molecular weight (Mr) of the ACTase enzyme from N. meningitidis showed it to be about 295,000, which resembles the class B enzymes found in the Enterobacteriaceae.
已对来自不同种奈瑟菌属和布兰汉菌属的天冬氨酸氨甲酰基转移酶（ACTase，EC 2.1.3.2）的调节特性进行了比较。观察到这些酶在调节性质上存在很大差异。ATP和GTP在脑膜炎奈瑟菌、淋病奈瑟菌以及其他九种球菌性“真奈瑟菌”属细菌中是正效应物。在包括卡他布兰汉菌在内的四种“假奈瑟菌”属细菌中，未观察到ATP或GTP的刺激作用。尽管长形奈瑟菌在分类学上与球菌性“真奈瑟菌”属细菌有亲缘关系，但在这些方面其表现与“假奈瑟菌”属细菌相同。除脑膜炎奈瑟菌和乳酸奈瑟菌外，CTP没有明显的刺激作用。CTP对长形奈瑟菌以及“假奈瑟菌”属细菌豚鼠奈瑟菌和卡他布兰汉菌的ACTase有强烈抑制作用。CTP对灰奈瑟菌、反硝化奈瑟菌以及“假奈瑟菌”属细菌绵羊奈瑟菌和兔奈瑟菌的抑制作用较弱。因此，在这些细菌群体中，CTP对ACTase的调节作用与分类学没有明显的对应关系。对18个物种中的5个物种所显示的天冬氨酸和氨甲酰磷酸的表观[S]0.5值表现出很大的变异性，天冬氨酸的[S]0.5值范围为6至34，氨甲酰磷酸的[S]0.5值范围为2至9。用热或对氯汞苯甲酸（pCMB）处理主要测试微生物脑膜炎奈瑟菌菌株M1的酶，结果表明催化功能和调节功能与假单胞菌属物种中发现的A类酶一样平行下降。对脑膜炎奈瑟菌ACTase酶的分子量（Mr）估计显示其约为295,000，这与肠杆菌科中发现的B类酶相似。
