Partial chemical characterization of the carbohydrate moieties in Leishmania adleri glycoconjugates.

Promastigotes of Leishmania adleri were submitted to an extraction procedure providing different carbohydrate-containing extracts. The purified aqueous extract showed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis a complex peptide pattern but carbohydrate was present only in bands of Mr approximately equal to 45 000-50 000 and 13 500. Methylated derivatives of the hexose components in this extract, analysed by mass spectrometry, suggest the presence of short sugar chains of alpha-D-mannopyranose and a branched alpha-D-mannan. The phenol extract, released in the aqueous layer a chloroform/methanol/water soluble complex contained 25% protein, 17% phosphate, 11% glucosamine, uronic acid and 61% neutral carbohydrate, and a chloroform/methanol/water insoluble fraction consisting of a glycoprotein Mr approximately equal to 22 000 and a proteic doublet Mr approximately equal to 58 000-66 000. A polysaccharide, showing galactose as predominant sugar, was released through alkaline extraction corresponding to a branched, mainly 1----3 linked galactan associated with alpha-D-mannopyranosyl units.