A simple method of calculating the molecular rotations of the sulfur, nitrogen and phosphorus analogues of α-D-glycopyranoses having different substituents at the anomeric carbon atom

The values of m and I of equation (1) for several series of α-D-glycopyranoses having different substituents at the anomeric carbon atom have been obtained earlier. From these values, the molecular rotations of the corresponding sugars containing a sulfur, nitrogen, or phosphorus atom in the ring have been calculated and found to agree satisfactorily with the corresponding literature values.

The β-glucosidase from Botryodiplodia theobromae Pat. Kinetics of enzyme-catalysed hydrolysis of o-nitrophenyl β-d-glucopyranoside in dioxan/water

1. The hydrolysis of o-nitrophenyl beta-D-glucopyranoside by the high-molecular-weight beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) from Botryodiplodia theobromae Pat. has been studied in the presence of added dioxan. 2. At donor saturation, the maximum rate of hydrolysis in the presence of up to 50%(v/v) dioxan was pH4.3-4.5 (pH of the buffer system in water) in McIlvaine's buffer. 3. Increasing dioxan concentrations progressively decreased the maximum rate of hydrolysis. 4. The rate of enzyme-catalysed reaction was enhanced at high donor concentrations, but inhibited at low donor concentrations in the presence of glycerol, methanol, fructose of sucrose. 5. The hydrolytic reaction was found to proceed with retention of configuration at the anomeric carbon atom. 6. The kinetics of the enzyme-catalysed process in the presence of added acceptors indicated that water was necessary for the maintenance of the active enzyme conformation apart from its acceptor function.