COORDINATE REPRESSION OF THE SYNTHESIS OF FOUR HISTIDINE BIOSYNTHETIC ENZYMES BY HISTIDINE

Coordinate Repression of the Synthesis of Four Histidine Biosynthetic Enzymes by Histidine.

Introduction.-In several instances, the rate of synthesis of the enzymes of a biosynthetic pathway appears to be regulated by the size of the pool of the end product of that pathway.1-4 This phenomenon has been called enzyme repression.2 We have observed repression by histidine during the investigation of the histidine biosynthetic enzymes in histidine-requiring mutants of Salmonella typhimuriu...

Sequential synthesis of histidine-degrading enzymes in Bacillus subtilis.

L-Histidine induces the formation of the four enzymes constituting the histidine-degrading pathway in Bacillus subtilis. Studies of the kinetics of induction of histidase and of FGA hydrolase demonstrated that the two enzymes appear after induction in sequence, separated by a Z-min interval. The results of experiments in which chloramphenicol was used to arrest peptide bond formation indicate t...

Histidine biosynthetic pathway in Staphylococcus aureus.

Induction and repression of the histidine-degrading enzymes of Bacillus subtilis.

In Baci2Zus subtilis a series of four enzymes is responsible for the degradation of L-histidine to ammonia, formamide, and L-glutamic acid. The third enzyme of the series was not investigated; the other three enzymes, histidase, urocanase, and formiminoglutamate hydrolase, are induced by r,-histidine and repressed by catabolites. Mutants can be found in which the three enzymes are constitutive ...

control of the optical properties of nanoparticles by laser fields

در این پایان نامه، درهمتنیدگی بین یک سیستم نقطه کوانتومی دوگانه(مولکول نقطه کوانتومی) و میدان مورد مطالعه قرار گرفته است. از آنتروپی ون نیومن به عنوان ابزاری برای بررسی درهمتنیدگی بین اتم و میدان استفاده شده و تاثیر پارامترهای مختلف، نظیر تونل زنی(که توسط تغییر ولتاژ ایجاد می شود)، شدت میدان و نسبت دو گسیل خودبخودی بر رفتار درجه درهمتنیدگی سیستم بررسی شده اشت.با تغییر هر یک از این پارامترها، در...