Glucosyl peptides

The structure of an unusual compound isolated from spores of Ustilago avenue46 has not yet been completely clarified. According to data available,189 it seems to be a cytidine 5 -(D-glucosyl phosphate) derivative having a peptide chain attached to a hydroxyl group of the D-ribose residue. 

The resistance of Bacillus cereus cell-wall peptidoglycan to lysozyme action200 is due to the majority of the 2-amino-2-deoxy-D-glucosyl residues having free (nonsubstituted) amino groups. Polysaccharide and peptide components of the cell walls were converted into material susceptible to lysozyme by N-acetylation with acetic anhydride. 

Fast-atom-bombardment mass spectrometry of a proteinase-truncated glucosyl-enzyme complex showed that the glucose was covalently linked as a /3-acetal ester to the carboxyl group of the aspartic acid located at the sixth residue from the N-terminal of the peptide ... 

Smythe, C., Caudwell, F. B., Ferguson, M., and Cohen, P. 1988. Isolation and structural analysis of a peptide containing the novel tyrosyl-glucosyl linkage in glycogenin. EMBO J. 7, 2681-2686. 

Experimental studies have shown that Leucinostatin A may be one of the several potentially toxic peptides produced by Acremonium sp. that contribute to the defense of the host. The host plant is relatively immune to Leucinostatin A, because it has an enzyme which transfers two glycosyl residues to leucinostatin A, thus reducing the peptide s bioactivity. From these results it can also be concluded that glucosylation reactions may play a general role in plant defenses, especially against toxin-mediated disease development [120]. 

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