The Amino-Acid Sequence of the αA2 Chain of Bovine α-Crystallin.

The αA₂ chain of bovine α-crystallin was fragmented by means of cyanogen bromide treatment and by tryptic, chymotryptic and thermolytic digestions. Twenty tryptic peptides were obtained from the S-aminoethylated αA₂ chain, accounting together for the complete sequence. The direct Edman degradation and the dansyl-Edman technique were used to determine the sequences of the tryptic peptides. The order of the tryptic peptides was deduced from overlapping peptides obtained by cyanogen bromide treatment, tryptic digestion of the maleylated chain and chymotryptic and thermolytic digestion of the S-aminoethylated chain. The sequence of the αA₂ chain comprises 173 residues and corresponds to a molecular weight of 19832. [ABSTRACT FROM AUTHOR]