The Amino Acid Sequence of β-Galactosidase

Abstract

Amino acid analyses of carboxymethylated /3-galactosidase isolated from Escherichia coli yielded 1,171 residues per molecular weight of 135,000.Sixty tryptic peptides, accounting for 643 residues and for 71 of the 100 lysine plus arginine residues, were isolated in pure form from a digest of the carboxymethylated protein using standard techniques and were analyzed for amino acids.The amino-terminal residues were determined with the Sanger reagent and the amide and tryptophan content was determined with aminopeptidase M.