Isolation, characterization and partial sequence of cyanogen bromide fragments and thiol peptides from pig kidney D-amino-acid oxidase.

Abstract A partial characterization of the primary structure of d -amino-acid oxidase ( d -Amino-acid:oxygen oxidoreductase (deaminating), EC 1.4.3.3) from hog kidney has been achieved by a CNBr cleavage of the 14 C-carboxymethylated protein. Four fragments have been isolated and purified and their alignment made possible by overlapping with methionine-containing peptides derived from tryptic digestion of the 14 C-carboxymethylated protein. A partial sequencing of the CNBr fragments has been carried out by the automated Edman procedure and by manual sequence analysis. Chymotryptic peptides containing the 5 alkylated thiols of the monomer enzyme (Curti, B., Ronchi, S., Branzoli, U., Ferri, G. and Williams, Jr., C. H. (1973) Biochim. Biophys. Acta 327, 266–273) have been isolated and their sequence determined. The present results do not show any significant homologies with the known sequences of other flavoproteins.