PURIFICATION AND CHARACTERIZATION OF A GLYCOPEPTIDE DERIVED FROM PHASEOLUS-VULGARIS LEUKOAGGLUTINATING PHYTHOHEMAGGLUTININ

A glycopeptide obtained from tryptic digestion of citraconylated leukoagglutinating (L-subunit) phytohemagglutinin was isolated and purified. The composition of its ten amino acid and seven hexose residues, when compared to a previous analysis of the NH2-terminal amino acid sequence, indicated that the glycopeptide was derived from residues 11 through 20, with the oligosaccharide unit linked N-glycosidically to asparagine at the twelfth position. Structural studies involving a combination of α-mannosidase digestion, periodate oxidation, and permethylation, in conjunction with computerized mass-spectrometric and masschromatographic techniques, suggested a branched sequence of five mannose and two glucosamine residues similar to that found in many mammalian glycoproteins. © 1979.