Protein metabolism denotes the various biochemical processes responsible for the synthesis of proteins and amino acids, and the breakdown of proteins (and other large molecules) by catabolism.
Dietary proteins are first broken down to individual amino acids by various enzymes and hydrochloric acid present in the gastro-intestinal tract. These amino acids are further broken down to α-keto acids which can be recycled in the body for generation of energy, and production of glucose or fat or other amino acids. This break-down of amino acids to α-keto acids occurs in the liver by a process known as transamination, which follows a bimolecular ping pong mechanism.
Protein biosynthesis relies on four processes:
Protein anabolism is the process by which protein are formed from amino acids (anabolic amino acid synthesis).