Define Analysis of Amino Acid sequence on Particular Peptide?

The analysis of the relative order or the sequence in which the ammo acids are arranged-along the length of the polypeptides is of greater significance. Studies of the structure of fibrinogen from different species have given valuable information on mammalian classification.

The amino acid sequences in the fibrinopeptide of 34 different species, mainly mammalian has been worked out and has proved especially suitable for taxonomic studies. This involves in splitting off the fibrinopeptide from the parent fibrinogen molecules by the action of thrombin. The fibrinogen molecule consists of the three polypeptide chain (a, P and y) linked by disulphide bridges. The proteolytic enzyme thrombin splits off two fibrinopeptides, one from the u and one from the P chain. It is in these two which . Are known as fibrinopeptide A and B, that the sequences have been worked out.

The classification of species worked out on basis of amino sequences in the peptides have been found to be in agreement with the general accepted schemes of classification based on morphology. So, it is possible to construct phylogenetic relationships within organisms on basis of the amino acid sequences in the peptides. Another peptide in which the amino acid sequences have been worked out and which has proved very useful in identification is the cytochrome C. This is present in the cells of all living organisms and contains about 110 amino acids, the sequence of which have been worked out for many animal species. It has been observed that the classification of species according to their amino acid sequences in the cytochrome C also fits fairly well with the current classification.