THE FRACTIONATION OF MYROTHECIUM VERRUCARIA CELLULASE BY GEL FILTRATION.

1. Culture filtrates from Myrothecium verrucaria have been fractionated by gel filtration on Sephadex G-75 to give three major cellulolytic components with molecular weights of about 55000, 30000 and 5300. 2. The middle component has the bulk (90%) of the total carboxymethylcellulase activity and is little affected by exposure to cotton. The other two, which are mainly responsible for the activity of the filtrate towards cotton, are removed or deactivated by exposure to it. These observations accord with the previously reported behaviour of the whole culture filtrate. There is no evidence for interconversion of, or synergism between, these components. 3. Temperature control during gel filtration is necessary for reproducible results at high resolution. The effect of a change in temperature has been explained in terms of changes in the degree of swelling of the gel particles.