Studies on marsupial proteins. IV. Amino acid sequence of myoglobin from the red kangaroo, Megaleia rufa

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.

Studies on marsupial proteins. I. Polymorphism of haemoglobin of the grey kangaroo, Macropus giganteus

A haemolysate of red blood cells of the grey kangaroo, M. giganteu8, gave several haemoglobin peaks when chromatographed on polycarboxylic-acid-type ion-exchange resins. In the four samples studied two major components, haemoglobin I and II, were present. In the sample examined in detail these comprised 51 and 45% respectively, together with about 4% of minor haem-containing proteins. The two major haemoglobin components were readily separated by chromatography at pH 6�4 in phosphate buffer of 0 �152M sodium-potassium ion concentration.