acid-phosphatase and thymolphthalein-monophosphate

Topics: Acid Phosphatase; Humans; Male; Phenolphthaleins; Prostate; Thymolphthalein

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.

Topics: Acid Phosphatase; Humans; Male; Nephelometry and Turbidimetry; Phenolphthaleins; Prostate; Quality Control; Reference Standards; Thymolphthalein; Time Factors

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.

Topics: Acid Phosphatase; Humans; Isoenzymes; Male; Nitrophenols; Organophosphorus Compounds; Prostatic Neoplasms; Radioimmunoassay; Thymolphthalein

We quantitated the concentrations of prostatic acid phosphatases (EC 3.1.3.2) in serum and bone-marrow aspirates with three commercial radioimmunoassay kits, and the catalytic activities with a thymolphthalein monophosphate-based enzyme test. The enzyme's immunological activity in serum was compared with its catalytic activity for its potential as a detector of early prostatic cancer and its performance as an early marker of metastatic activity in bone. Neither measurement is useful for detecting early stages of prostatic cancer. The spread of carcinoma to lymph nodes or to bone is detected with greater frequency by radioimmunoassay than by the enzymic test. Radioimmunoassay also detected metastasis to the bone more frequently than did physical methods. Analytical and clinical performance of the four methods is described.

Topics: Acid Phosphatase; Adolescent; Adult; Aged; Bone Marrow; Clinical Enzyme Tests; Female; Humans; Male; Middle Aged; Prostate; Prostatic Neoplasms; Radioimmunoassay; Reagent Kits, Diagnostic; Thymolphthalein

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.

Topics: Acid Phosphatase; Chromatography, High Pressure Liquid; Humans; Kinetics; Male; Phenolphthaleins; Prostate; Reference Standards; Spectrophotometry; Thymolphthalein

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.

Topics: Acid Phosphatase; Choline; Clinical Enzyme Tests; Colorimetry; Humans; Male; Phenolphthaleins; Phosphorylcholine; Prostate; Prostatic Neoplasms; Thymolphthalein