Abstract
We previously reported the occurrence of oligomannosides and xylomannosides corresponding to unconjugated N-glycans (UNGs) in the medium of a white campion (Silene alba) cell suspension. Attention has been focused on these oligosaccharides since it was shown that they confer biological activities in plants. In an attempt to elucidate the origin of these oligosaccharides, we studied two endoglycosidase activities, putative enzymes involved in their formation. The previously described peptide-N4-(N-acetyl-glucosaminyl) asparagine amidase activity and the endo-N-acetyl-beta-D-glucosaminidase activity described in this paper were both quantified in white campion cells during the culture cycle with variable initial concentrations of sucrose. The lower the sucrose supply, the higher the two activities. Furthermore, endoglycosidase activities were greatly enhanced after the disappearance of sugar from the medium. The production of UNGs in the culture medium rose correlatively. These data strongly suggest that the production of UNGs in our white campion cell-suspension system is due to the increase of these endoglycosidase activities, which reach their highest levels of activity during conditions of carbon starvation.
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Selected References
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- Bourgerie S., Berger S., Strecker G., Julien R., Karamanos Y. A fluorescence high-performance liquid chromatography assay for enzymes acting on the di-N-acetylchitobiosyl part of asparagine-linked glycans. J Biochem Biophys Methods. 1994 Jun;28(4):283–293. doi: 10.1016/0165-022x(94)90004-3. [DOI] [PubMed] [Google Scholar]
- Priem B., Gitti R., Bush C. A., Gross K. C. Structure of ten free N-glycans in ripening tomato fruit. Arabinose is a constituent of a plant N-glycan. Plant Physiol. 1993 Jun;102(2):445–458. doi: 10.1104/pp.102.2.445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wittenbach V. A. Purification and characterization of a soybean leaf storage glycoprotein. Plant Physiol. 1983 Sep;73(1):125–129. doi: 10.1104/pp.73.1.125. [DOI] [PMC free article] [PubMed] [Google Scholar]