Amino acid sequence of the .beta. chain of human fibrinogen

Abstract
The .beta.-chain of human fibrinogen contains 461 amino acid residues; 15 are methionines. The calculated MW, independent of a single carbohydrate cluster is 52,230. In this regard, all 16 cyanogen bromide fragments were isolated and characterized. In 1 case (CNI), a disputed portion of a previously reported fragment was concentrated on. The arrangement of the cyanogen bromide peptides was deduced by using overlap fragments obtained from the tryptic digestion of modified and unmodified .beta.-chains, from digestions with staphylococcal protease and by considerations involving the plasmic digestion products of fibrinogen. In 1 case 2 adjacent fragments were aligned by homology with the corresponding segments of the .gamma.-chain. The homology of the .beta.-chain with the .gamma.-chain is especially strong over the course of the carboxy-terminal 2/3 of the sequence. Neither chain appears homologous with the .alpha.-chain in these regions. With a few minor exceptions, the sequence reported is in agreement with data reported by others.