Studies on plant gums: Part III--Isolation and characterization of a glycopeptide from neem (Azadirachta indica) gum after pronase digestion
Nayak, B.R.; Pattabiraman, T.N.
Indian Journal of Biochemistry and Biophysics 15(6): 449-455
1978
ISSN/ISBN: 0301-1208 PMID: 753744 Document Number: 134729
Neem gum solution was highly resistant to attack by several proteases tested. Gum solution subjected to prior heat treatment for 10 min at 98.degree. C was hydrolyzed by pronase, subtilisin BPN and Aspergillus oryzae protease effectively. Chromatographic studies of the pronase digest on TEAE--cellulose revealed the presence of a high MW heteropolysaccharide associated with small amounts of protein. A glucosamine-rich glycopeptide was isolated in a homogenous form from the pronase digest by chromatography on TEAE-cellulose and Bio-Gel P-10. The glycopeptide accounted for about 60% of glucosamine in the native gum. It had a MW in the region of 2000 daltons. The glycopeptide contained arabinose, galactose and glucosamine in the proportion 2.96:2.0:4.9. The constituent amino acids of the glycopeptide were asparagine, serine, threonine, arginine, proline, valine, phenylalanine and tyrosine. The link in the glycopeptide is the glucosaminyl asparaginyl bond.