New efforts will be made toward the further purification of the solubilized chitin synthetase. Mutants defective in chitin synthesis will be studied genetically and biochemically. The subcellular distribution and pattern of action of a chitinase present in yeast will be investigated in an attempt to understand its physiological significance. The study of a chitinase from wheat germ will be completed. This enzyme will be used, after attachment to colloidal gold particles, to ascertain the distribution of chitin in yeast bud scars and in nascent buds. The activation of yeast glucan synthetase by ATP and by an activator from yeast will be further studied, to ascertain their function in the regulation of yeast growth.