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At least 19 recordsLinked to original sources
PubMed1983

Effects of substrate concentration on results of determination of prostatic acid phosphatase with thymolphthalein monophosphate.

The relation between concentration of thymolphthalein monophosphate substrate and catalytic activity was investigated for the determination of prostatic acid phosphatase. This study, an extension of previously reported work (Clin. Chem. 27: 1372, 1981), shows that lot-to-lot variation in purity of thymolphthalein monophosphate preparations is reflected in substrate-velocity curves. Plateau regions in these curves at 1.5-2.5 g/L result from the combined effects of (a) substrate concentrations that are an order of magnitude below Km and (b) a further decrease in available substrate caused by formation of substrate aggregates in the presence of serum. To simplify the identification of superior lots of thymolphthalein monophosphate, we give a mixed-substrate protocol for testing different lots.

Acid Phosphatase↗
PubMed1983

Presumptive screening test for seminal acid phosphatase using sodium thymolphthalein monophosphate.

The use of sodium thymolphthalein monophosphate for presumptive seminal acid phosphatase testing is discussed. Recent evidence reveals that the dye (o-dianisidine) used in conjunction with alpha-naphthyl phosphate for seminal acid phosphatase testing is a carcinogenic hazard. Numerous tests for seminal acid phosphatase were conducted with swabs from sexual assault kits to compare both substrates. Results of tests using sodium thymolphthalein or alpha-naphthyl phosphate correlated exactly. Sodium thymolphthalein is an effective alternative for preliminary seminal fluid analysis because of its high degree of selectivity and stability, and because it eliminates the potential health hazard.

Acid Phosphatase↗
PubMed1981

A clinical assay for prostatic acid phosphatase using choline phosphate as a substrate: comparison with thymolphthalein phosphate.

We describe an assay method using choline O-phosphate as a substrate for the measurement of serum prostatic acid phosphatase as an aid in the diagnosis of prostatic cancer. Choline phosphate is hydrolyzed by homogeneous prostatic acid phosphatase, and it is also hydrolyzed by an acid phosphatase present in the serum of prostatic carcinoma patients. In contrast, serum samples from apparently healthy persons do not exhibit any significant choline O-phosphate phosphatase activity. There is a correlation of 98% (n = 46) between choline O-phosphate phosphatase activity and typical measurement for prostatic acid phosphatase activity carried out using thymolphthalein monophosphate as the substrate. The new method appears to be as accurate as colorimetric methods based on thymolphthalein phosphate as a substrate. Although not as sensitive as immunologically based methods, the present technique for measuring prostatic acid phosphatase activity using choline phosphate as a substrate is economical and relatively simple.

Acid Phosphatase↗
PubMed1981

Spectrophotometric and liquid-chromatographic studies of thymolphthalein monophosphate. Specifications for high-quality substrate for the measurement of prostatic acid phosphatase activity.

Fourteen lots of thymolphthalein monophosphate (TMP), disodium salt, obtained from 10 commercial suppliers were compared spectrophotometrically at 445 and 595 nm, liquid-chromatographically with monitoring at 254 nm, and enzymically by measurements of activity of prostatic acid phosphatase in human serum. Eight lots were classified as "unacceptable," six as "acceptable." Spectrophotometric testing revealed four lots with excessive thymolphthalein and three lots with grossly deficient amounts of TMP. In general, the chromatographic results paralleled those obtained by spectrophotometry, and both results correlated well with enzymic activity. Changing water content in this hygroscopic salt was a major problem, which resulted in great uncertainty as to the formula weight and therefore as to the moles of TMP actually taken. From these studies, specifications for high-quality TMP were determined. The critical importance of simultaneous enzymic activity measurements in comparisons with other "acceptable" lots in defining an adequate TMP substrate is stressed. Use of these specifications for selecting TMP for acid phosphatase activity measurements should improve intra- and inter-laboratory analytical performance.

Acid Phosphatase↗
PubMed1975

Enhancing effect of surfactant and protein on hydrolysis of thymolphthalein monophosphate by purified prostatic acid phosphatase.

Purified prostatic acid phosphatase catalyzes the hydrolysis of thymolphthalein monophosphate 10-fold faster if an optimal concentration of Brij 35 (a wetting agent) or protein (bovine serum albumin or human serum proteins) is present. Results of gel filtration, dialysis, and sucrose density-gradient centrifugation analysis suggest that the substrate must combine with detergent or protein before the enzyme can catalyze its hydrolysis.

Acid Phosphatase↗
PubMed1976

Improved determination of prostatic acid phosphatase (sodium thymolphthalein monophosphate substrate).

We have modified a previously described method for determining acid phosphatase, with thymolphthalein monophosphate as substrate, to increase its sensitivity. We assessed effects of serum on variables influencing acid phosphatase activity as measured by this method. The method is shown to be not completely specific for prostatic acid phosphatase. The importance of standardizing methodology in measurement of enzyme activities is demonstrated.

Acid Phosphatase↗
PubMed1997

Analysis of nifedipine-acebutolol hydrochloride binary combination in tablets using UV-derivative spectroscopy, capillary gas chromatography and high performance liquid chromatography.

Three methods are described for the simultaneous determination of nifedipine and acebutolol hydrochloride in combined pharmaceutical tablets. The first method depends on first-derivative ultraviolet spectrophotometry, with peak-to-base and zero-crossing measurements methods. The first derivative amplitudes at 400 and 352 nm were selected for the assay of nifedipine and acebutolol hydrochloride, respectively. Calibration graphs follow Beer's law in the range of 4-12 and 44-132 micrograms ml-1 and the linearity was satisfactory (r = 0.999) for nifedipine and acebutolol hydrochloride, respectively. The second method was based on the separation of nifedipine from acebutolol hydrochloride, with an internal standard thymolphthalein, using capillary gas-liquid chromatography with a programmable temperature change. The third method was based on high performance liquid chromatographic separation of the two drugs on a reversed-phase, C18, column using a mobile phase of methanol-water (55:45, pH 4.5) with a programmable flow rate of 1 ml min-1 for 4 min which changed to 2 ml min-1 for the rest of the run. The detection was done at 260 nm using oxprenolol hydrochloride as an internal standard. Both chromatographic methods showed good linearity, precision and reproducibility. No spectral or chromatographic interference from the tablet excipients were found. The proposed methods were successfully applied to the assay of commercial tablets and a content uniformity test. The procedures were rapid, simple nondestructive and suitable for quality control application.

Acebutolol↗
PubMed1982

Comparison of radioimmunological and conventional acid phosphatase assays in the serum of prostatic cancer patients.

Measurements of serum prostatic acid phosphatase concentrations (PAP) by radioimmunoassay (RIA) were compared with the conventional measurements of serum acid phosphatase activities using p-nitrophenylphosphate (pNPP, tot.) and magnesium thymolphthalein monophosphate (TMP) as substrates and L(+)-tartrate (pNPP, tr.) as inhibitor in five prostatic cancer patients before therapy and in 13 during therapy. Elevated serum acid phosphatase activities were detected in 2, 2 and 3 of the 5 untreated patients when using pNPP (tot.), pNPP (tr.) and TMP enzyme assays, respectively. RIA for PAP detected elevated concentrations of the enzyme in 4 of these patients' sera. Three of the patients without metastases and one patient with suspected metastases had elevated concentrations of PAP by RIA. Serum acid phosphatase isoenzyme 2, which is mainly of prostatic origin, was separated chromatographically from serum samples with increased acid phosphatase activity. It represented 60--92% of the total activity, when TMP was used as substrate. Significant correlations (beta less than 0.001) were observed between all conventional enzyme activity measurements used and PAP by RIA within the whole patient group (n = 18), but no correlations existed within the patient group (p = 6) of high normal, or low abnormal serum PAP (2.7--6.6 micrograms/l). In addition, PAP measured by RIA better reflected the clinical state of the 13 patients under treatment than the conventional enzyme assays investigated.

Acid Phosphatase↗