Studies on Marsupial Proteins IV. Amino Acid Sequence of Myoglobin From the Red Kangaroo, Megaleia Rufa

Abstract

Myoglobin isolated from skeletal muscle of M. rufa consists of a single component containing 153 amino acid residues. The complete amino acid sequence has been determined. Oleavage with cyanogen bromide gave four polypeptides which were further fragmented by digestion with trypsin or chymotrypsin. The amino acid sequences of the peptides obtained were determined by the "dansyl"-Edman procedure. The order of the cyanogen bromide fragments was readily deduced from terminal sequences. Digestion of maleylated myoglobin with trypsin and cleavage at histidine residues with N-bromosuccinimide gave some overlapping sequences. Amino acid sequences in myoglobins are more conservative than in the ,B-chains of haemoglobin previously studied (Air and Thompson 1969) but the red kangaroo myoglobin shows more variation in amino acid sequence than has been found in myoglobins from other species.