摘要：

Two general methods for the synthesis of acyl coenzyme A and other thiol esters are described in this chapter. The first procedure an acid anhydride is allowed to react with the mercaptan in cold aqueous solution at pH 7.5. The second method makes use of thiol ester interchange reactions of the type. In the synthesis of simple thiol esters by the anhydride and mixed anhydride procedures, the yields are normally 80 to 100%, based on the free —SH. The formation of thiol ester derivatives of α, β-unsaturated fatty acid is much poorer—15 to 50%. These low yields are because of the occurrence of side reactions in which the –SH groups add to the double bonds of. the anhydride and thiol esters. In addition to the general methods, thiol esters have been prepared by reaction of mereaptans with acyl chlorides and thiol acids. A method for the synthesis of acetoacetyl thiol esters by reaction of mercaptans with ketene has been presented. In enzymatic assay of Ac-SCoA measurement is made of the decrease in optical density at 232 to 240 mμ that is associated with the hydrolysis of Ac-SCoA. The complete hydrolysis of Ac-SCoA is brought about in a few seconds by incubation in the presence of phosphotransacetylase and arsenate.

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