COMPLETE AMINO-ACID SEQUENCE OF THE BETA-SUBUNIT OF PROTOCATECHUATE 3,4-DIOXYGENASE FROM PSEUDOMONAS-AERUGINOSA

The complete amino acid sequence of the β9-subunit of protocatechuate 3,4-dioxygenase is presented. The β9-subunit contained 237 amino acid residues, 4 of which were methionines. Accordingly, cyanogen bromide cleavage of the S-carboxymethylated β-subunit produced five peptides. The sequences of these peptides were determined by analyses of the peptides obtained by tryptic, staphylococcal protease and thermolysin digestions. The alignment of the cyanogen bromide peptides was deduced by the use of overlapping peptides containing methionine which were obtained by tryptic digestion of the S-carboxymethylated β-subunit. The calculated molecular weight was 26,588, which is close to the value estimated by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. © 1979, by the Japanese Biochemical Society.