Thymolphthalein monophosphate

Acid phosphatase catalyzes the dephosphorylation of an artificial organic substrate, such as B-glycerophosphate, phenyl-phosphate or thymolphthalein monophosphate. The analyst may measure either the phosphate or the organic radical liberated. 

Roy, A. V. Brown, M. E. and Hayden, J. E. Sodium thymolphthalein monophosphate, a new acid phosphatase substrate with greater specificity for the prostatic enzyme in serum. Clin. Chem. (1971), IJ, 1093-1102. 

In practice it is often more convenient to measure the release of a phenol from an aryl phosphomonoester. Standard serum phosphatase methods employ phenyl phosphate (188), p-nitrophenyl phosphate (189), phenolphthalein monophosphate (140), or thymolphthalein monophosphate (141) where the phenol released can be determined spectrophoto-metrically [only the Bodansky method (13) uses a Pi determination]. A number of fluorogenic substrates have been used for phosphatase studies, e.g., jS-naphthyl phosphate (30, 148), 4-methylumbelliferyl phosphate (143), and 3-O-methylfluorescein phosphate (144) The main advantage here is the much greater sensitivity of fluorescence as compared with spectrophotometric assays as little as 1 pmole of 4-methyl-umbelliferone can be detected in continuous assay. 

Fig. 3 Structures of chromogenic phosphatase substrates (a) Para-nitrophenyl phosphate (b) phenolphthalein monophosphate (c) thymolphthalein monophosphate...

Ewen LM, Spitzer RW (1976) Improved determination of prostatic acid phosphatase (sodium thymolphthalein monophosphate substrate). Clin Chem 22 627-632... 

Coleman CM (1966) The synthesis of thymolphthalein monophosphate, a new substrate for alkaline phosphatase. Clin Chim Acta 13 401-403... 

Foti A G Herschman H Cooper J F iruFeld H. Enhancing effect of surfactant and protein on hydrolysis of thymolphthalein monophosphate by purified prostatic acid phosphatase. Clin. Chem. 1975, 21, 1761-1765. 

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