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PubMed1977

[Ultrastructural localization of thyrocyte acid phosphatase in the presence of thyrocyte hyperfunction in rats].

Acid phosphatase was found by electron microscopy in the lysosomes which appeared in great numbers in the follicular cells of rat hyperplastic thyroid gland. The other types of granules (mature secretory granules and lipids) whose amounts were also greatly increased in cases of functional thyrocyte strain were also nonreactive. The lysosomes were subdivided into three main groups according to distribution of the reaction product: the lysosomes with dense homogeneous deposit and with deposit in the form of densely or loosely packed dark round granules. The lysosome heterogeneity was apparently connected with their different functions also found within the colloid droplets in the form of inclusions of rarely located dark granules. The authors believe such granules to be the result of the merging of the colloid droplets and lysosomes. The acid phosphatase of the latter participated in the hydrolysis of the product of cell secretion with the formation of active substances.

Acid Phosphatase↗
PubMed1983

Induction of acid phosphatase and cholinesterase activities in Ps. aeruginosa and their in-vitro control by choline, acetylcholine and betaine.

Choline, acetylcholine and betaine used as a sole carbon source, effectuate in Ps. aeruginosa an acid phosphatase activity in addition to a cholinesterase activity. Induction of both enzyme activities was repressed by succinate or glucose. Cyclic AMP failed to relieve the repression produced by these compounds. Substrates not related to choline and used as a sole source of carbon, were inefficient to produce induction of both enzymes. The in-vitro action of choline, acetylcholine and betaine on Ps. aeruginosa acid phosphatase and cholinesterase has also been studied. To perform these studies periplasmic extracts obtained by EDTA-lysozyme treatment of the cells grown on choline or betaine as sole source of carbon, were used. Acid phosphatase activity was competitively inhibited by betaine, whereas the inhibition produced by choline and acetylcholine showed competitive and noncompetitive components. Cholinesterase activity was noncompetitively inhibited by betaine. At low acetylthiocholine concentration choline was an inhibitor of cholinesterase, whereas at high substrate concentration choline raised the hydrolysis rate of acetylthiocholine. These findings allow the conclusion that acid phosphatase and cholinesterase are specifically induced by choline and its metabolites derivatives. Kinetic results led us to postulate that acid phosphatase and cholinesterase contain a similar allosteric site. This site would either be of an anionic nature or show affinity to a methyl group or display both characteristics.

Acetylcholine↗
PubMed1990

The zinc test as an alternative for acid phosphatase spot tests in the primary identification of seminal traces.

The value of the acid phosphatase spot test in the primary visualization and identification of seminal traces is hampered by the sensitiveness of the enzyme to biodegradation. An alternative spot test is proposed, based on the high concentration of the more stable zinc metal in seminal plasma. The proposed zinc spot test is simple and suitable for on site investigation. Although the sensitivity in fresh stains is lower than that of the acid phosphatase spot test, this is largely compensated by the lower sensitiveness to biodegradation. The specificity for semen is higher than that of the acid phosphatase spot test. In vaginal swabs it was nevertheless seen, that samples should be taken within 24 h after alleged sexual assault to give reliable results.

Acid Phosphatase↗
PubMedDate not supplied

Purification and characterization of human seminal plasma acid phosphatase.

A 81-fold purification of human seminal plasma acid phosphatase was obtained by a three-step procedure, involving ammonium sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. Homogeneity of the preparation during purification steps was tested by polyacrylamide gel electrophoresis and only one major band was obtained after the final step. The pH optimum for the activity of the purified enzyme was 5.6 and thermal stability was obtained even up to 40 degrees C. PNPP was the most specific synthetic substrate. The Km of purified seminal acid phosphatase towards PNPP was 1.5 X 10(-3) M. Among the metal ions tested, Hg+2 showed an I50 value of 4.2 X 10(-7) M. Studies with PCMB, PMSF and EDTA did not show any inhibition, whereas NaF and L(+)tartrate, at 1 mM concentration, inhibited the enzyme by 95% and 85%, respectively.

Acid Phosphatase↗
PubMed1989

An immunoassay of human band 5 ("tartrate-resistant") acid phosphatase that involves the use of anti-porcine uteroferrin antibodies.

We describe an immunoassay for human band-5 acid phosphatase in which antibodies to porcine uteroferrin, immobilized on Sepharose particles, are used. Band-5 acid phosphatase is the tartrate-resistant isoenzyme normally expressed in tissue macrophages such as osteoclasts and alveolar macrophages. The immunoassay is similar in reproducibility and sensitivity to assays based on inhibition by d-tartrate. However, compared with the latter, the greater specificity of the immunoassay makes it markedly less susceptible to errors arising from the presence of non-band-5 acid phosphatases, e.g., from prostate.

Acid Phosphatase↗
PubMed2005

Crystallization of a newly discovered histidine acid phosphatase from Francisella tularensis.

Francisella tularensis is a highly infectious bacterial pathogen that is considered by the Centers for Disease Control and Prevention to be a potential bioterrorism weapon. Here, the crystallization of a 37.2 kDa phosphatase encoded by the genome of F. tularensis subsp. holarctica live vaccine strain is reported. This enzyme shares 41% amino-acid sequence identity with Legionella pneumophila major acid phosphatase and contains the RHGXRXP motif that is characteristic of the histidine acid phosphatase family. Large diffraction-quality crystals were grown in the presence of Tacsimate, HEPES and PEG 3350. The crystals belong to space group P4(1)2(1)2, with unit-cell parameters a = 61.96, c = 210.78 A. The asymmetric unit is predicted to contain one protein molecule, with a solvent content of 53%. A 1.75 A resolution native data set was recorded at beamline 4.2.2 of the Lawrence Berkeley National Laboratory Advanced Light Source. Molecular-replacement trials using the human prostatic acid phosphatase structure as the search model (28% amino-acid sequence identity) did not produce a satisfactory solution. Therefore, the structure of F. tularensis histidine acid phosphatase will be determined by multiwavelength anomalous dispersion phasing using a selenomethionyl derivative.

Acid Phosphatase↗
PubMed2001

Endogenous lectin as a possible regulator of the hydrolysis of physiological substrates by soybean seed acid phosphatase.

The effects of two lectins concanavalin A (conA) and soybean agglutinin, on soybean seed acid phosphatase activity were investigated using p-nitrophenylphosphate (pNPP), pyrophosphate (PPi) and phosphoenolpyruvate (PEP) as substrates. Of the four acid phosphatase isoforms (AP1, AP2, AP3A and AP3B) purified from soybean seeds, only AP1 was activated 40 and 60% by conA and soybean agglutinin, respectively. Both lectins affected some of the kinetic parameters of AP1. The activation by lectins was not affected by 1 mM Ca2+ or Mn2+ but glucose and methylmannopyranoside (100 mM) prevented activation by conA. Under the same conditions, galactose had no effect. These results suggest that plant acid phosphatases may be regulated by lectins, the effects vary according to the substrate used.

Acid Phosphatase↗
PubMed1983

Lack of value of radioimmunoassay for prostatic acid phosphatase as a screening test for prostatic cancer in patients with obstructive prostatic hyperplasia.

We examined the incidence of prostatic cancer in patients with an elevated radioimmunoassay for prostatic acid phosphatase and clinical benign prostatic hyperplasia on digital rectal examination. Of 295 patients screened with prostatic acid phosphatase tests 17 fulfilled the criteria of having an elevated prostatic acid phosphatase, clinically benign prostate and histological examination of the prostatectomy specimen. None of the 17 patients had histological evidence of prostatic cancer. The results confirm the predictions of mathematical models that prostatic acid phosphatase is of no practical value as a screening test for prostatic cancer in patients with clinical benign prostatic hyperplasia.

Acid Phosphatase↗
PubMed1976

Purification of protoplast-secreted acid phosphatase from baker's yeast. Effect on adenosine triphosphatase activity.

In order to examine acid phosphatase (EC 3.1.3.2) and ATPase (EC 3.6.1.3) activities of baker's yeast (pH optimum 3.5) a protoplast-secreted enzyme preparation was purified and some physical and chemical properties were studied. Three protein fractions containing ATPase and acid phosphatase activities, in the same ratio as the initial preparation, were separated by ion-exchange chromatography. The first fraction which had the highest protein content yielded a homogeneous preparation after Sepharose 4B chromatography and was used in further studies. An attempt to estimate molecular weight of this protein was made. Attempts to separate acid phosphatase and ATPase activities by ion-exchange chromatography, gel filtration, isoelectric focusing and sucrose density gradient centrifugation have been unsuccessful. Both activities behaved the same way to heat and urea denaturation. These results suggest that the two activities are associated with the same protein molecule.

Acid Phosphatase↗
PubMed1984

Comparison of acid phosphatases in the rat prostatic complex and seminal vesicles.

Acid phosphatase activity of different parts (ventral, lateral and posterior lobes and coagulating gland) of the rat prostatic complex and seminal vesicles were analyzed in homogenate and after fractionation with gel filtration and chromatofocusing. Significant differences between the various tissue homogenates were recorded in the hydrolysis of p-nitrophenyl phosphate, alpha-naphthyl phosphate and naphthol ASBI phosphate and the percentage of the tartrate-resistant activity varied from about 30 (in seminal vesicles) to 56 (in coagulating gland). Gel filtration resulted in the appearance of 2 (Sephadex G-200) to 3 (Sepharose 6B) activity peaks (GF-1 to GF-3). Studies with 6 substrates (p-nitrophenyl phosphate, alpha-naphthyl phosphate, beta-naphthyl phosphate, naphthol ASBI phosphate, phenolphthalein phosphate and thymolphthalein phosphate) showed some relative differences in the hydrolysis rates as well as indications for possible overlapping of multiple enzymes in these peaks. Chromatofocusing of the ventral prostate homogenate resulted in the appearance of 8 activities (CF-1 to CF-8) with different pI-values (8.2, 8.1, 7.9, 7.1, 6.4, 6.0, 5.5, and 5.0), substrate preferences, pH-optima (5.5, 4.2, 4.2, 6.0, 5.5, 5.0, 4.2, and 5.0), molecular weights and modifier characteristics. The other tissues contained a lower number of these activities: 4 (CF-1 to CF-3 and CF-6) in lateral and posterior lobes and coagulating gland and 5 (CF-1 to CF-4 and CF-6) in seminal vesicles. The correspondence of the enzyme peaks after gel filtration and chromatofocusing was analyzed by refractionation. This indicated that some of the enzymes (GF-1, CF-5, CF-8) may appear in polymeric/aggregate forms. The differences in the acid phosphatase pattern suggest characteristic functional features in the various parts of the rat prostatic complex.

Acid Phosphatase↗
PubMed1982

Circadian and day-to-day variation of prostatic acid phosphatase.

The circadian and day-to-day variation of serum levels of prostatic acid phosphatase determined by radioimmunoassay was investigated in 10 men with a normal prostate, 8 with benign prostatic hyperplasia and 10 with prostate cancer. Serum samples were obtained on 1 day at 8 a.m., 12:00 noon and 4:30 pm. in 23 patients, and on 3 consecutive days at 8 a.m. in an additional 5 patients. There was a variability in enzyme level throughout the day but without any distinct pattern. Prostate cancer patients with elevated levels of prostatic acid phosphatase did demonstrate a greater variability throughout the day than patients with a normal prostate or with benign prostatic hyperplasia. The day-to-day serum prostatic acid phosphatase in patients with a normal prostate varied little and remained within the normal range.

Acid Phosphatase↗
PubMed1998

Identification of a histidine acid phosphatase (phyA)-like gene in Arabidopsis thaliana.

A close examination of the protein sequence encoded by the Arabidopsis thaliana gene F21M12.26 reveals the gene product to be a phosphomonoesterase, acid optimum (EC 3.1.3.2). A subclass of this broad acid phosphatase is also known as 'histidine acid phosphatase. ' This is the first sequence-based evidence for a 'histidine acid phosphatase' in a dicotyledon. One important member of this class of enzymes is Aspergillus niger (ficuum) phytase, which came into prominence for its commercial application as a feed additive. The putative protein from A. thaliana gene F21M12.26 shares many important features of Aspergillus phytase, namely, size, active-site sequence, catalytic dipeptide and ten cysteine residues located in the key areas of the molecule, but lacks all nine N-glycosylation sites.

Acid Phosphatase↗
PubMed1996

Influence of growth temperature on the acid phosphatase activity in the yeast Yarrowia lipolytica.

The adaptation of the yeast Yarrowia lipolytica 76-18 to growth temperature was studied by measuring the levels of secreted and intracellular acid phosphatase activities during growth at five temperatures from 8 to 36 degrees C. The intracellular acid phosphatase activity is maximal at a growth temperature of 20 degrees C. The level of the secreted phosphatase activity decreases as growth temperature increases from 15 to 36 degrees C. It is the growth temperature itself and not the growth rate that regulates these activities. The observed dependence of the acid phosphatase activity on the growth temperature indicates a possible participation of acid phosphatases in the temperature adaptation of yeast cells.

Acid Phosphatase↗
PubMed1994

[Serum levels of the tartrate-resistant isoenzyme, acid phosphatase, for the evaluation of bone remodeling in hyperthyroidism].

Tartrate-resistant acid phosphatase (TRAP) is one of the acid phosphatase isoenzymes. It is secreted by osteoclasts so it has been proposed as a marker of bone resorption. Bone turnover is high in hyperthyroidism due to an increase in both bone resorption and formation. The aim of the study was to measure serum TRAP as well as other markers of bone metabolism in 20 fertile age females affected by Graves-disease; 11 patients were also studied after euthyroid state was attained by means of a 6 month course of methimazole treatment. TRAP was measured with the colorimetric method using p-nitrophenylphosphate as substrate. Free thyroid hormones, TSH, serum calcium (corrected for albumin concentration), phosphate, osteocalcin, alkaline phosphatase, parathormone intact molecule, and urinary excretions of calcium, phosphate and hydroxyproline were measured, too. Twenty-eight healthy fertile women made up the control group. Untreated patients had a significant increase of TRAP, osteocalcin, serum calcium, alkaline phosphatase and urinary excretion of calcium and hydroxyproline. A significant fall in all these parameters but alkaline phosphatase was disclosed comparing patients before and after treatment, nevertheless only urinary calcium became not significantly different from the controls. TRAP showed a significant correlation with free T3 levels but not with hydroxyproline excretions. This survey on fertile age women with Graves' disease shows a significant increase in serum concentration of TRAP, which decreases, but doesn't get normalization, when euthyroidism is attained by a six month course of methimazole therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1982

An acid phosphatase in the plasma membranes of human astrocytoma showing marked specificity toward phosphotyrosine protein.

The plasma membrane from the human tumor astrocytoma contains an active acid phosphatase activity based on hydrolysis of p-nitrophenyl phosphate. Other acid phosphatase substrates--beta-glycerophosphate, O-phosphorylcholine, and 5'-AMP--are not hydrolyzed significantly. The phosphatase activity is tartrate insensitive and is stimulated by Triton X-100 and EDTA. Of the three known phosphoamino acids, only free O-phosphotyrosine is hydrolyzed by the membrane phosphatase activity. Other acid phosphatases tested from potato, wheat germ, milk, and bovine prostate did not show this degree of specificity. The plasma membrane activity also dephosphorylated phosphotyrosine histone at a much greater rate than did the other acid phosphatases. pH profiles for free O-phosphotyrosine and phosphotyrosine histone showed a shift toward physiological pH, indicating possible physiological significance. Phosphotyrosine histone dephosphorylation activity was nearly 10 times greater than that seen for phosphoserine histone dephosphorylation, and Km values were much lower for phosphotyrosine histone dephosphorylation (0.5 microM vs. 10 microM). Fluoride and zinc significantly inhibited phosphoserine histone dephosphorylation. Vanadate, on the other hand, was a potent inhibitor of phosphotyrosine histone dephosphorylation (50% inhibition at 0.5 microM) but not of phosphoserine histone. ATP stimulated phosphotyrosine histone dephosphorylation (160-250%) but inhibited phosphoserine histone dephosphorylation (95%). These results suggest the existence of a highly specific phosphotyrosine protein phosphatase activity associated with the plasma membrane of human astrocytoma.

Acid Phosphatase↗
PubMed1979

The ultrastructural localization of secretory acid phosphatase in giant cell tumor of bone.

Three cases of giant cell tumor of bone were studied with the light and electron microscopes to determine the histochemical and cytochemical distribution of acid phosphatase isoenzymes. Using beta-glycerophosphate as a nonspecific substrate, acid phosphatase was found in the giant cells as well as the stromal cells. Ultrastructurally, using this substrate, the enzyme was found to be associated with lysosomes in the stromal cells and giant cells and also with the profuse system of tubules and vesicles in the cytoplasm of the giant cells. Using phosphorylcholine and D-ephedrinephosphate, which are substrates for a specific secretory isoenzyme of acid phosphatase, activity was found only in the vesicles of the giant cell cytoplasm. Lysosomes did not show activity with these substrates. Multinucleated cells of giant cell tumor contain a specific secretory type of acid phosphatase which is not present in the stromal cells. This suggests that the giant cells are attempting to form a secretory system similar to osteoclasts and that the vesicles in the cytoplasm which contain this acid phosphates are the morphologic expression of an abortive secretory system.

Acid Phosphatase↗
PubMed1990

Bovine brain low Mr acid phosphatase: purification and properties.

Low molecular weight acid phosphatase from bovine brain was purified to homogeneity using affinity chromatography on p-aminobenzylphosphonic acid-agarose to obtain the enzyme with both high specific activity (110 mumol min-1 mg-1 measured at pH 5.5 and 37 degrees C with p-nitrophenyl phosphate as substrate) and good yields. The enzyme was characterized with respect to molecular weight, amino acid composition, pH optimum, Km and Vmax in varying substrates, and to the Ki of varying inhibitors. Furthermore, transphosphorylation to glycerol was demonstrated by measuring the released p-nitrophenol/Pi concentration ratio during the initial phase of the catalyzed reaction. The enzyme was inactivated by iodoacetate and 1,2-cycloexanedione. Inorganic phosphate, a competitive inhibitor, protected the enzyme from being inactivated by the above compounds, demonstrating the involvement of both cysteine(s) and arginine(s) at the active site of the enzyme. Furthermore, the strong inhibition exerted by pyridoxal 5'-phosphate and the low inhibitory capacity possessed by the pyridoxal 5'-phosphate analogues pyridoxamine 5'-phosphate and pyridoxal, indicate that at least one lysine residue is present at the active site.

Acid Phosphatase↗
PubMed1977

Localization of acid phosphatase activity in the liver of pregnant rats.

In the liver of pregnant rats, fed ad libitum, there was an increase in acid phosphatase specific activity which occurred in two peaks, one at the 15th day and the other at the end of gestation. By light and electron microscopic histochemistry, the activity was found to be localized in parenchymal cell peribiliary dense bodies and also in phagosomes present in macrophages and parenchymal cells. There was an increase in liver wieght which reached a peak at the 17th day of gestation. Total DNA also rose to the 17th day; there was a high rate of cell division in the hepatic parenchyma at the 17th and 18th days of gestation. During this period single cell deletion by apoptosis was relatively frequent and in late pregnancy there was evidence of cell deletion by lysis. During pregnancy there was a slight increase in sinusoidal macrophages as a proportion of the total cell population but there did not appear to be significant changes in macrophage enzymic activity. It is suggested that the acid phosphatase activity present in macrophages makes a minor contribution to total liver activity, most of which is present in parenchymal cells. Acid phosphatase activity associated with single cell deletion appears to be quantitatively negligible. There was a direct relationship between total hepatic acid phosphatase activity and the numbers of peribiliary dense bodies, which were most numerous at the 15th day and at the end of gestation. It is suggested that these residual bodies contain products of detoxification processes and also cell structural elements resulting from enhanced liver metabolism and intracellular turnover during pregnancy.

Acid Phosphatase↗