1. A method is described for the estimation of thiol ester groups. The thiol ester is converted into the corresponding thiol by reaction with ammonia; the thiol is then titrated amperometrically with mercuric chloride. 2. The method may be used in the presence of SH and S.S groups. The SH groups are titrated at pH3 in the presence of excess of chloride; under these conditions thiol esters do no...

p-Nitrophenyl N-butyl, N-octyl, and N-dodecyl carbamates and a newly synthesized diethyl phosphate compound were studied as potential inhibitors of the cholesteryl ester hydrolases of Fu5AH rat hepatoma cells. Whole homogenates of Fu5AH cells were used as an enzyme source for the assay of cholesteryl ester hydrolase activity. All four compounds led to marked inhibition (70-80%) of neutral chole...

[formula: see text] Aminocyclodextrins are known to bind phosphate esters such as phosphotyrosine and p-nitrophenyl phosphate. This paper describes the inhibition of phosphate ester hydrolysis, as catalyzed by lambda-protein phosphatase and acid phosphatase, that is caused by such binding interactions. ROESY studies provide structural information about the cyclodextrin-aryl phosphate complexes....

The nucleophilic catalysis by a pyridyl group in ester/phosphate ester hydrolysis was modulated by the microenvironmental hydrophobicity around the catalyst. The catalytic efficiency was enhanced thousands or tens of thousands of times and the activity was maintained well below the pKa of the pyridyl group.

“Phosphotransferase” activity, which has been previously described (l), involves the enzymic transfer of phosphate from various aryl phosphates to particular hydroxyl compounds, apparently without the mediation of a nucleotide. It was indicated in this work that the phosphate group was transferred directly from the donor to the acceptor compound. The main basis for this belief was the observati...

Glucose-l-phosphoric acid was first isolated from minced and washed frog muscle which had been incubated for 3 hour in phosphate buffer containing small amounts of adenylic acid (2). Under these conditions part of the glucose-l-phosphoric acid (l-ester) was converted to hexose-6-phosphoric acid (8ester), so that fractional crystallization of the brucine salts had to be resorted to as a means of...

Release paper is a special paper grade with one or both sides coated with non-sticking materials. Silicone is currently the only material used to produce release paper at the industrial level. Its remarkable properties and availability ensure product quality and sustainability of the industrial production. Meanwhile, the stability of silicone polymers raises serious environmental problems in te...