The amino acid sequence in a fraction of the fibroin of Bombyx mori.

1. Methyl-O-fl-D-fructofuranoside has been prepared by the action of yeast invertase on sucrose in the presence of methanol. 2. The fructoside has been used as a substrate for a mould-enzyme preparation (Taka-diastase). An examination of the products showed that both hydrolysis and transfructosylation occurred. 3. Sucrose could not be detected among the products of action upon mixtures of methyl ,Bfructoside and glucose, either by chromatographic fractionation or by the use of 14C-labelled glucose. 4. Taka-diastase acting on mixtures of raffinose and glucose formed sucrose. The incorporation of radioactive glucose into the molecule demonstrated that sucrose formation was the result of fructose transfer and not of melibiase (cx-galactosidase) action. 5. The implications of these findings are discussed in relation to the hypothesis that invertases form fructosyl-enzyme compounds as common intermediates in hydrolysis and transfructosylation.