6533b820fe1ef96bd127996f

RESEARCH PRODUCT

Separation of chitosomal chitin synthetase from cell-free extracts ofNeurospora crassa “Slime” variant agglutinated with concanavalin A

subject

description

Cell-free extracts of the wall-less slime variant ofNeurospora crassa were treated with concanavalin A (Con A); this treatment caused a massive agglutination of the particulate structures in the cell-free homogenate, although most (73%) of the chitin synthetase initially present in the cell-free extract remained in the supernatant obtained after sedimentation of the lectin-flocculated material. This chitin synthetase showed the sedimentation properties of chitosomes (unique microvesicular structures) and failed to bind [3H]Con A. A significant percentage (42%) of the chitin synthetase activity associated with the Con A-flocculated material probably corresponds to mechanically trapped chitosomes, whereas the rest of the activity in the Con A-agglutinated material might be a genuine part of the flocculated membranes and could represent a physiologically distinct form of the enzyme.