Mh. Straver et al., ISOLATION AND PARTIAL-PURIFICATION OF MANNOSE-SPECIFIC AGGLUTININ FROM BREWERS-YEAST INVOLVED IN FLOCCULATION, Yeast, 10(9), 1994, pp. 1183-1193
Yeast cell-agglutinating activity, designated agglutinin (possible lec
tin), was isolated from cell walls of both non-flocculent and floccule
nt brewer's yeast cells. Agglutinin-mediated aggregation of yeast cell
s in a manner similar to flocculation with respect to specific mannose
-sensitivity, pH-dependence and calcium-dependence. Agglutinating acti
vity was found to be heat-stable and protease-insensitive. Furthermore
, addition of agglutinin to flocculent cells strongly stimulated the f
locculation ability of the cells, whereas addition to non-flocculent c
ells rendered these cells weakly flocculent. Agglutinin was found to b
e released from flocculent cells during the course of a flocculation a
ssay, but not from non-flocculent cells. Presence of mannose during th
e assay inhibited release of agglutinin. Our results suggest that (i)
mannose-specific agglutinin is continuously synthesized during growth
of brewer's yeast cells, (ii) agglutinin is present in cell walls of n
on-flocculent cells but is unable to bind its ligand on other cells, a
nd (iii) the ability of yeast cells to flocculate in a flocculation as
say depends, among other factors, on release of agglutinin from the ce
lls. A 10-kDa polypeptide might represent one form of agglutinin.