Related Experiment Video
Updated: May 6, 2026

Concanavalin A-Based Sedimentation Assay to Measure Substrate Binding of Glucan Phosphatases
Published on: December 23, 2022
Transport and processing of the glycosylated precursor of Concanavalin A in jack-bean
1Department of Biology, University of California/San Diego, C-016, 92093, La Jolla, CA, USA.
Abstract:
Concanavalin A (ConA) is a tetrameric lectin which is synthesized in the developing cotyledons of jack bean (Canavalia ensiformis L.) as a glycosylated precursor, pro-concanavalin A (pro-ConA). The processing of pro-ConA involves the excision of a small glycopeptide from the center of the pro-ConA molecule, and the ligation of the two polypeptides. In this paper, we show that pro-ConA is associated with the endoplasmic reticulum/Golgi fraction of the cells, and that the processing of pro-ConA occurs in the protein bodies. Processing is a complex process and different intermediate-sized polypeptides appear at different times during cotyledon development. The ConA-related polypeptides which accumulate during seed development may be the products of alternate processing events or breakdown products of ConA, rather than precursors of ConA. When glycosylation is prevented by tunicamycin, there is very little transport of pro-ConA out of the endoplasmic reticulum/Golgi system to the protein bodies; the unglycosylated pro-ConA which is transported is slowly processed. Tunicamycin does not prevent the transport of canavalin (a protein which is not glycosylated) or the transport and processing of the small amounts of glycosylated pro-ConA synthesized in the presence of the drug. This is, to our knowledge, the first demonstration that the transport of a glycoprotein in plant cells is dependent on the presence of the glycan.
More Related Videos
11:47Residue-specific Incorporation of Noncanonical Amino Acids into Model Proteins Using an Escherichia coli Cell-free Transcription-translation System
Published on: August 1, 2016
20:23A Lectin HPLC Method to Enrich Selectively-glycosylated Peptides from Complex Biological Samples
Published on: October 1, 2009
Related Concept Videos
Protein Folding Quality Check in the RER
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
Protein Transport to the Inner Chloroplast Membrane
Export of Misfolded Proteins out of the ER
Protein Transport to the Stroma
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
Mitochondrial Precursor Proteins
Most of the mitochondrial...