Glycosides mechanism

Smith TW, Antman EM, Friedman PL, Blatt CM, Marsh JD. Digitalis glycosides mechanisms and manifestations of toxicity. Prog Cardiovasc Dis 1984 26(6) 495-540 1984 27(l) 21-56. 

The mechanism for formation of the 3 methyl glycoside is shown The mechanism for for mation of the a isomer is the same except that methanol approaches the carbocation from the axial direction... 

Naturally occurring compounds called cyanogenic glycosides, such as lotau-stralin, release hydrogen cyanide, HCN, when treated with aqueous acid. The reaction occurs by hydrolysis of the acetal linkage to form a cyanohydrin, which then expels HCN and gives a carbonyl compound-fa) Show the mechanism of the acetal hydrolysis and the structure of the cyanohydrin that results. 

Cardiac glycosides have a small ratio of toxic to therapeutic concentration. Possible adverse effects are nausea, vomiting, abdominal pain, diarrhoea, fatigue, headache, drowsiness, colour vision disturbances, sinus bradycardia, premature ventricular complexes, AV-block, bigeminy, atrial tachycardia with AV-Block, ventricular fibrillation. There are several mechanisms relevant for their toxic action (Table 2). 

All of Hamao U mezawa s work was closely connected with carbohydrates. The principal compounds that he developed, namely, kanamycin, dibekacin (with the elucidation of the resistance mechanism), kasugamycin, formycin, bleomycin, and anthracyclines, are all glycosides. The l.m.w. enzyme-inhibitors, exemplified by bestatin, are mostly oligopeptides, and are the only exceptions. 

In this article are discussed the results of those studies which have become available over the past 15 years and which permit some generalizations on the catalytic mechanism of glycoside hydrolases from widely differing sources and with different sugar and aglycon specificities. It will be seen that, with few exceptions, the data support a mechanism almost identical to that proposed by Phillips and his group for lysozyme. ... 

The hydrolysis of glycosides by acid and by enzymes is one of the most important reactions encountered in the carbohydrate field. The mechanisms... 

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