protein for life
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function . A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between The carboxyl and amino groups of adjacent amino acid residues . The sequence of amino acids in a protein is defined by the sequence of a gene , which is encoded in the genetic code . In general, the genetic code specifies 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteine and in certain archaea pyrrolysine . Shortly after or even during synthesis, the residues in a protein are often chemically modified by posttranslational modification , which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofacto...