Enzymatic Synthesis of 1,5-Anhydro-4-O-β-D-glucopyranosyl-D-fructose Using Cellobiose Phosphorylase and Its Spontaneous Decomposition via β-Elimination

Cellobiose phosphorylase from Cellvibrio gilvus was used to prepare 1,5-anhydro-4-O-β-D-glucopyranosyl-D-fructose [βGlc(1→4)AF] from 1,5-anhydro-D-fructose and α-D-glucose 1-phosphate. βGlc(1→4)AF decomposed into D-glucose and ascopyrone T via β-elimination. Higher pH and temperature caused faster decomposition. However, decomposition proceeded significantly even under mild conditions. For instance, the half-life of βGlc(1→4)AF was 17 h at 30 °C and pH 7.0. Because βGlc(1→4)AF is a mimic of cellulose, in which the C2 hydroxyl group is oxidized, such decomposition may occur in oxidized cellulose in nature. Here we propose a possible oxidizing pathway by which this occurs.     

Monoamine oxidase in developing chick retina

The developmental changes in monoamine oxidase (MAO) activities towards 5-hydroxytryptamine (5-HT) and beta-phenylethylamine (PEA) in chick retina were investigated. The whole pattern of the developmental changes in MAO activity towards 5-HT was similar to that towards PEA, even though the activity towards 5-HT was much lower than that towards PEA during the period from the 12th day of incubation to the 14th day after hatching. The MAO activities on the 12th day of incubation were low and increased remarkably until the 18th day of incubation. Then they remained unchanged until the 7th day after hatching; therefore, they decreased. The activities measured on the 14th day after hatching are on the same level as those of an adult. The multiplicity of MAO in the retinae of a chick on the 12th day of incubation and of an adult was also studied with specific inhibitors. The result showed that the major part of MAO in chick retina is type B enzyme; that type A MAO in the retina of an adult is, however, relatively higher than that in the retina of the embryo on the 12th day of incubation. It was found that an appreciable amount of MAO activity towards 5-HT in chick retina is due to type B MAO.