ISSN:
1573-4986
Keywords:
dolichol pathway
;
GlcNAc-P-P-dolichol
;
GlcNAc-GlcNAc-P-P-dolichol
;
antibiotics
;
inhibition
;
stimulation
;
retina
;
showdomycin
;
diumycin
;
amphomycin
;
bacitracin
;
microsomes
;
embryonic chick
;
kinetics
;
Dionex
;
GlcNAc-P-P-dolichol, N-acetylglucosaminylpyrophosphoryldolichol
;
GlcNAc-GlcNAc-P-P-dolichol, N-acetyl-glucosaminyl-N-acetylglucosaminylpyrophosphoryldolichol
;
TX-100, triton X-100
;
Tes, 2-{[tris-(hydroxy-methyl)-methyl]-amino}-ethanesulfonic acid
;
chitobiose, GlcNAc-GlcNAc
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The antiobiotics, diumycin, amphomycin, bacitracin, and showdomycin have been shown previously to block the synthesis of GlcNAc-P-P-dolichol and GlcNAc-GlcNAc-P-P-dolichol. In view of inconsistencies in the literature concerning the sites of inhibition, we have reinvestigated the influence of these drugs on the formation of these early intermediates of the dolichol pathway. Unexpectedly, when the individual products of the reactions were examined, instead of inhibition, showdomycin and bacitracin were found to stimulate the formation of GlcNAc-P-P-dolichol, and diumycin stimulated at low concentrations. Three derivatives of showdomycin were examined with similar results, showing stimulations of GlcNAc-P-P-dolichol formation of up to two-fold over controls. Amphomycin specifically inhibited GlcNAc-P-P-dolichol formation, an effect that was reversed by a high concentration of dolichyl phosphate. In contrast, with the exception of amphomycin, each compound directly inhibited the formation of GlcNAc-GlcNAc-P-P-dolichol. Using chemically synthesized GlcNAc-P-P-dolichol as substrate, the kinetics of inhibition of GlcNAc-GlcNAc-P-P-dolichol formation by showdomycin, bacitracin and diumycin was examined. The apparent Ki values calculated from these studies indicated that showdomycin was the most active inhibitor. These findings provide a new understanding of the action of these compounds on the GlcNAc-transferases of the dolichol pathway. © 1998 Rapid Science Ltd
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006982003957
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