1. ATCase [aspartate transcarbamoylase] catalyzes the first step in pyrimidine biosynthesis. In bacteria pyrimidine nucleotide biosynthesis is regulated by a feedback inhibition. ATCase is inhibited by CTP [cytidine 5?-triphosphate], the end product of pyrimidine biosynthesis. This is an allosteric regulation.
The activation by ATP and inhibition by CTP ...
This solution includes a discussion and diagrams and mechanisms for ATCase and PALA. 210 words.