Concanavalin with mannans

Concanavalin A is an antibody-like protein isolated from the jack bean. 82 It was shown to form a precipitate with glycogen and with yeast mannan, and was later also used to differentiate between glycogen-like polysaccharides from various sources.283 284 It has now been shown that concanavalin A forms a precipitate only with branched polysaccharides which contain terminal, nonreducing a-D-glucopyranosyl or a-D-manno-pyranosyl groups.18 The combining sites of the protein appear to be directed against the 2-deoxy-a-D-aratano-hexopyranosyl system.2 ... 

This aspect becomes more important in relation to analytical procedures requiring expensive reagents and the turbidimetric determination of yeast mannan [16] is a good example. The antigen reacted with the expensive antibody concanavalin A therefore, the reagent addition via merging zones and a 1.0-min STOP period were required. 

Targeted drug delivery systems for the anticancer drug Taxotere were built from jS-CyD by monoconjugation with mannosyldendritic branches. Binding inhibition of horseradish peroxidase-labeled Concanavalin A to yeast mannan by mannosylated yS-CyDs was examined. The IC50 values of 95, 96, 97, 98, and 99 were 800, 780, 91, 110, and 8 pM, respectively. 97 solubilized Taxotere similarly to monobranched CyDs [34]. The solubility of Taxotere in water can by increased 1000-fold by 97. 

Histochemical staining at the cell surface of yeast-like forms, hyphae, and conidia of Sporothrix schenckii cell-types with iron(lll) hydroxide and ferritin has been shown to correspond to the locations of concanavalin A-reactive peptido-L-rhamno-D-mannan complexes in the cells. 

The binding of concanavalin A (tetrameric) and succinylated concanavalin A (dimeric) to a yeast Schizosaccharomyces pombe) mannan gel has been studied. o-Mannans on thin sections of S. cerevisiae and C. utilis cells can be located with either the homologous antibodies or concanavalin A labelled with colloidal gold. Fully synthesized D-mannan was detected in the cell walls, on the plasmalemma, and in the cytoplasm, sometimes associated with vesicles and vacuoles. 

The chemistry and immunostimulant properties of the cell walls of mycobacteria and related organisms have been reviewed. Concanavalin A has been shown to react with three antigenic polysaccharides present in culture filtrates of Mycobacterium tuberculosis, these polysaccharides were isolated by direct precipitation and affinity chromatography. A mannan esterified with succinic acid has been isolated from extracts of mesosomal and plasma membranes of Micrococcus lysodeikticus The polysaccharide was precipitated by concanavalin A, but it was attacked only slightly by jack-bean a-mannosidase. I.r. spectroscopy indicated the presence of both esterified and free carboxy-groups in the mannan. Mesosomal membranes isolated from M. lysodeikticus, unlike preparations of plasma membranes, were unable to catalyse the incorporation of D-[ C]mannose from GDP-D-[ C]mannose into the mannan it appears that the membrane system is unable to synthesize the carrier lipid undecaprenyl D-mannosyl phosphate. It was suggested that the juxtaposition of the mesosomal vesicles and the enveloping plasma membrane in vivo allows the mannan located on the mesosomal vesicles to accept D-mannosyl units from the carrier lipid located in the plasma membrane. 

Mannans.—A j8-(l -> 3)-glucanase has been used to prepare protoplasts from C. utilis and S. cerevisiae. Scanning electron microscopy of prefixed protoplasts, using colloidal gold labelled with concanavalin A, showed that the D-mannan is distributed randomly at the surface of the protoplasts. 

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