Glutamic acid, aspartic acid and their amides occupy an important place in the metabolism of nitrogenous compounds. We know that glutamic acid was the main entry point of ammonia into biological compounds and we will see that its metabolism is linked to that of several other amino acids; as for its amide, glutamine, it plays an important role in the [...]
It is not surprising that the metabolism of these two aromatic amino acids is closely linked because they differ only by the presence of a phenolic OH in the tyrosine molecule. We will not study here their biosynthesis which — in organisms where it takes place, especially bacteria — starts from 2 compounds of the carbohydrate metabolism (erythrose-4-℗ and phosphocnolpyruvate) [...]
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 [...]