In connection with the tryptophan operon, that an excess of tryptophan can cause a repression of the genes of this operon, leading to an arrest of the synthesis of the enzymes required for the formation of tryptophan. Beside this possibility of repression, there is very often feedback inhibition, i.e. the possibility for an essential metabolite (amino acid, nucleotide, etc.), which [...]
In this article we will discuss about the synthesis and absorption of amino acids. Synthesis of Amino Acids: E.coli and many other micro-organisms can be grown in an inorganic medium with glucose added as the only source of carbon, which definitely shows that all amino acids can be synthesized by these cells from glucose. It may be considered that plants [...]
The below mentioned article provides a note on protein metabolism. Notion of Nitrogen Balance: If one determines, on the one hand, the quantity of nitrogen ingested by an animal and on the other hand the quantity excreted in urine and faeces, one may observe three situations: i. The nitrogen excreted is less than the nitrogen ingested, i.e. there is retention [...]