Mh. Straver et al., PURIFICATION AND PARTIAL CHARACTERIZATION OF A FLOCCULIN FROM BREWERS-YEAST, Applied and environmental microbiology, 60(8), 1994, pp. 2754-2758
Analysis of a shear supernatant from flocculent, ''fimbriated'' Saccha
romyces cerevisiae brewer's yeast cells revealed the presence of a pro
tein involved in flocculation of the yeast cells and therefore designa
ted a flocculin. The molecular mass of the flocculin was estimated to
be over 300 kDa, as judged from sodium dodecyl sulfate-polyacrylamide
gel electrophoresis. Gel permeation chromatography of the flocculin yi
elded an aggregate with an apparent molecular weight of >2,000. The fl
occulin was found to be protease sensitive, and the sequence of its 16
N-terminal amino acids revealed at least 69% identity with the predic
ted N tenninus of the putative protein encoded by the flocculation gen
e FLO1. The flocculin was isolated from flocculent S. cerevisiae cells
, whereas only a low amount of flocculin, if any, could be isolated fr
om nonflocculent cells. The flocculin was found to stimulate the flocc
ulation ability of flocculent yeast cells without displaying lectinlik
e activity (that is, the ability to agglutinate yeast cells).