Glucose enzymatic cleavage

Returning to the pathway beyond vincoside, formation of the Corynanthe family requires no skeletal rearrangement and is regarded as involving enzymatic cleavage of glucose as a first step as in Scheme Geissoschizine (41),... 

However, nucleoside diphosphates (NDP) are still expensive substrates, which can be obtained from much more cheaper nucleoside monophosphates (NMP). In this respect we have combined the SuSy-catalyzed cleavage of sucrose with the enzymatic formation of NDPs from NMPs catalyzed by nucleoside monophosphate kinase (NMPK, EC 2.7.4.4) or myokinase (MK, EC 2.7.4.3), including in situ regeneration of ATP with pyruvate kinase (PK, EC 2.7.1.40) (Fig. 20) [272]. Testing the substrate spectrum of four different kinases disclosed that none of them accepted dTMP as substrate [272], However, dUMP was well accepted by NMPK and dUDP-activated glucose could also substitute dTDP-activated glucose as precursor for the synthesis of activated deoxysugars (see below). The excellent enzyme stabilities under synthesis... 

Catechol, hydroquinone, and pyrogallol can be produced from glucose by the enzymatic methods of Frost and co-workers (see Chap. 9). Catechol can also be obtained by the demethylation and cleavage of lignin, the polymer that holds wood together.45 Frost and co-workers have shown how to convert catechol to adipic acid. Thus, the lignin from wood, which is now underutilized, might be converted into nylon. 

Examples of enzymes used for biosensors include glucose oxidase for glucose sensors, alcohol oxidase for ethanol sensors, lactate oxidase for lactate sensors and urease for urea sensors. A typical enzyme reaction, as described by equation 5.2 might involve the transfer of an electron, a pH change, hydrolysis, esterification or bond cleavage. The type of enzymatic reaction that occurs determines the type of transducer that is used. 

There are several studies supporting the latter possibility. Brady s (1963) proposal that an enzymatic defect resulted in impairment of cleavage of the ceramide-glucose bond of the cerebrosides, was supported by studies on cerebrosides... 

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