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PubMed1978

Multiple forms of acid phosphatase activity in Gaucher's disease.

Although the primary genetic defect in all individuals with Gaucher's disease is a deficiency in glucocerebrosidase activity, the finding of marked elevations in splenic and serum acid phosphatase activity is almost as consistent a finding. Gaucher spleen and serum contain at least two forms of acid phosphatase that can be readily separated by chromatography on columns containing the cation exchange resin Sulphopropyl Sephadex. The major species of acid phosphatase (designated SP-I) contained in Triton X-100 (1% v/v) extracts of Gaucher spleen accounts for 65%--95% of the total activity and has the following properties: (1) it does not bind to the cation exchange column; (2) it exhibitis a pH optimum of 4.5--5.0; (3) it is inhibited by sodium fluoride (15 mM), L(+)-tartaric acid (20 mM), and beta-mercaptoethanol (2.1 M), and (4) it is resistant to inhibition by sodium dithionite (10 mM). The minor acid phosphatase activity (designated SP-II) present in extracts of Gaucher spleen has properties similar to those of the major species of acid phosphatase activity contained in serum from patients with Gaucher's disease: (1) it binds firmly to cation exchange columns (eluted by 0.5 M sodium chloride); (2) it exhibits a pH optimum of 5.0--6.0; (3) it is inhibited by sodium fluoride and sodium dithionite; and (4) it is resistant to inhibition by beta-mercaptoethanol (2.1 M) and L(+)-tartaric acid (20 mM). In addition, a second form of acid phosphatase that is tartrate resistant was found to be elevated in Gaucher serum. This form of serum acid phosphatase did not bind to Sulphopropyl Sephadex, was found to be significantly resistant to beta-mercaptoethanol (2.1 M), and was only partially inhibited by sodium dithionite (10 mM). The findings reported here indicate that at least three distinct forms of acid phosphatase activity are elevated in Gaucher's disease. Furthermore, the minor acid phosphatase activity contained in spleen homogenates has properties very similar to those of the major acid phosphatase activity observed to be present in serum of patients with Gaucher's disease. These data indicate that simple spleen spillage cannot account for the increased levels of serum acid phosphatase in patients with Gaucher's disease.

Acid Phosphatase↗
PubMed2000

Purple acid phosphatases from bacteria: similarities to mammalian and plant enzymes.

Mammalian and plant purple acid phosphatases have similar active site structures despite low sequence identity (<20%). Although no bacterial enzyme has been purified, a sequence database search revealed that genes that could encode potential purple acid phosphatases may be restricted to a small number of organisms (i.e. myco- and cyanobacteria). Analysis of their deduced amino acid sequences and predicted secondary structures indicates that the cyanobacterial enzyme is similar to both the mammalian and the recently discovered low-molecular-weight plant purple acid phosphatases, while the mycobacterial enzyme is homologous to the fungal and high-molecular-weight plant purple acid phosphatases. Homology models indicate that both bacterial proteins appear to be similar to mammalian purple acid phosphatases in the immediate vicinity of the active site. It is likely that these enzymes act as Fenton-type catalysts in order to prevent damage caused by reactive oxygen species generated by invaded host cells (M. tuberculosis) or by the light-harvesting complex (Synechocystis sp.).

Acid Phosphatase↗
PubMed1982

Isolation, characterization, and spontaneous interconversion of two forms of human prostatic acid phosphatase.

Starting with human prostatic acid phosphatase (HPAP) purified by affinity chromatography on Sepharose-bound N-(6-aminohexyl)tartramic acid [Van Etten, R. L. and Saini, M. S. (1978) Clin. Chem. 24, 1525], two forms of the enzyme can be separated by gradient elution DEAE-cellulose chromatography. The two enzyme forms are electrophoretically distinguishable on high pH gels. Under some conditions of storage one of these forms undergoes a conversion to the other. Both forms have identical amino acid compositions and Vmax values with typical substrates, but differences are observed in circular dichroism spectra, relative fluorescence intensities, Km values, and carbohydrate composition. It is concluded that the two forms differ only in the structure of their (nonphosphorylated) carbohydrate side chains. In view of the possible interconversion of the two forms upon storage, caution must be observed in any attempt to attach clinical significance to the relative amounts of the two forms.

Acid Phosphatase↗
PubMed1979

Significance of "high" acid phosphatase activity in the serum of normal children.

Serum acid phosphatase activity in normal children (newborn to 18 years) is several fold that in normal adults. Activity is age-related but not sex-related. The isoenzyme pattern in children is similar to that in adults and contains no prostatic fraction. Quantitatively, most of the enzyme activity in the serum of children is tartrate-resistant and correlates well with heat-labile fractions of alkaline phosphatase activity in serum, suggesting that the source of the higher acid phosphatase activity in children is bone. Significant tartrate-resistant acid phosphatase activity was demonstrated in the giant cells in three patients with giant-cell tumors, but not in the "osteoblasts" in six patients with osteogenic sarcomas and many other normal or abnormal tissues. This work suggests that the higher enzyme activity in the serum of children represents a normal physiological phenomenon resulting from their greater osteoclastic activity.

Acid Phosphatase↗
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↗
PubMed1999

Crystallization and preliminary X-ray diffraction studies of mammalian purple acid phosphatase.

The oxidized form of purple acid phosphatase from pig allantoic fluid has been crystallized in the presence of phosphate using the hanging-drop technique. The crystals belong to the space group P2(1)2(1)2(1) and have unit-cell parameters a = 66.8, b = 70.3, c = 78.7 A. Diffraction data collected from a cryocooled crystal using a conventional X-ray source extend to 1.55 A resolution. A knowledge of the three-dimensional structure of mammalian purple acid phosphatase will aid in understanding the substrate specificity of the enzyme and will be important in the rational design of inhibitors, with potential in the treatment of bone diseases.

Acid Phosphatase↗
PubMed1976

Release and activation of a particulate bound acid phosphatase from Tetrahymena pyriformis.

A sedimentable form of acid phosphatase (EC 3.1.3.2) from Tetrahymena pyriformis was found to be solubilized by Triton X-100. The total enzyme activity in the insoluble cell fraction increased almost 200% upon solubilization with Triton X-100 or Nonidet P-40. Removal of membrane lipids and Triton X-100 from the particulate wash solution with a chloroform extraction resulted in non-specific enzyme-protein aggregation which was reversible upon addition of Triton X-100. The results indicate that this acid phosphatase is an integral membrane protein. The pH optima for this particulate bound acid phosphatase was 3.5 with o-carboxyphenyl phosphate and 4.0 with p-nitrophenyl phosphate as substrates. The Km values of each substrate were 3.1 and 0.031 mM, respectively.

Acid Phosphatase↗
PubMed1985

Activity of acid phosphatase in resting and mitogen-stimulated human peripheral blood lymphocytes.

Activity of acid phosphatase was found to be higher in T than in non-T cells of human peripheral blood lymphocytes. The T cell mitogen PHA induced an increase in the magnitude of acid phosphatase activity, while the B cell mitogen LPS was not able to produce any effect on acid phosphatase activity. Acid phosphatase activity in lymphocytes correlated with their spontaneous proliferative activity.

Acid Phosphatase↗
PubMed1991

Characterization of a tartrate-resistant acid phosphatase (ATPase) from rat bone: hydrodynamic properties and N-terminal amino acid sequence.

Certain physicochemical properties of rat bone tartrate-resistant acid ATPase (TrATPase), including the size and shape of the enzyme, potential subunit composition, and detergent binding, have been elucidated. SDS-polyacrylamide gel electrophoresis in combination with immunoblot analysis showed that the bone TrATPase has a molecular weight of 33,000 D and is composed of disulfide-linked polypeptides of 20,000 and 16,000 D. The enzyme contains 1.7 mol Fe per mol enzyme. Hydrodynamic studies allowed calculation of the Stokes radius (24 A), the sedimentation coefficient (3.19S), the partial specific volume (0.748 ml/g), the frictional ratio (0.995), and the axial ratio (1.0). The amount of detergent bound to the protein was determined to 4 mol of Triton X-100 per mol enzyme. The molecular weight of bone TrATPase derived from these parameters was 31,900 D. N-terminal amino acid sequence analysis of the Mr 20,000 subunit indicated a high degree of similarity with TRAP enzymes from spleen, uterus, placenta, hairy cell leukemia, and osteoclastoma. It is concluded that rat bone TrATPase belongs to the type 5 (tartrate-resistant and purple) acid phosphatase family. The similarities in the N-terminal amino acid sequences, iron content, and physicochemical properties of TRAP enzymes indicate a close structural relationship between type 5 acid phosphatases expressed in different tissues. The findings that TrATPase has a spherical shape and binds low amounts of detergent suggest that the enzyme is a soluble protein, compatible with the view that TrATPase is secreted by the osteoclast.

Acid Phosphatase↗
PubMed1995

High-level expression of endogenous acid phosphatase inhibits growth and vectorial secretion in Saccharomyces cerevisiae.

The secretion pathway of Saccharomyces cerevisiae was challenged by constitutively overexpressing plasmid-encoded acid phosphatase, a secreted endogenous glycoprotein. A 2-microns-based multicopy plasmid carrying the coding sequence of acid phosphatase under the control of a truncated variant of the strong constitutive glyceraldehyde-3-phosphate dehydrogenase promoter was used for expression. Selection for the promoterless dLEU2 marker leads to a growth arrest. This is not per se due to leucine starvation, but due to intracellular accumulation of highly glycosylated enzymatically active acid phosphatase. Immunofluorescence and cytological analysis indicate that intracellular accumulation of acid phosphatase occurs in a subpopulation of cells. By Ludox-AM density centrifugation, these cells can be enriched on the basis of their higher density. The dense accumulating cells have a higher average plasmid copy number and produce more acid phosphatase than non-accumulating cells of low density. These cells are defective in directed secretion and bud formation, therefore can no longer grow and show dramatic changes in cell morphology. We suggest that the secretion pathway in these cells is overloaded with the high level of acid phosphatase leading to a shutdown in vectorial secretion, subsequently to a standstill in growth and to the intracellular accumulation of further expressed acid phosphatase. We have indications that accumulation of acid phosphatase occurs in the late Golgi, suggesting a limitation of the overall secretion at this stage.

Acid Phosphatase↗
PubMed2004

Isolation and partial characterisation of acid phosphatase isozymes from dormant oilseed of Corylus avellana L.

The acid phosphatase (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) complement from dormant hazel (Corylus avellana L.) seeds was found to exhibit significant electrophoretic heterogeneity partially attributable to the presence of distinct molecular forms. In axiferous tissue, total acid phosphatase activity increased in a biphasic fashion during chilling, a treatment necessary to alleviate seed dormancy. Three acid phosphatase isozymes were isolated from cotyledons of dormant hazel seeds by successive ammonium sulphate precipitation, size-exclusion, Concanavalin A affinity, cation- and anion-exchange chromatographies resulting in 75-, 389- and 191-fold purification (APase1, APase2, APase3, respectively). The three glycosylated isoforms were isolated to catalytic homogeneity as determined by electrophoretic, kinetic and heat-inactivation studies. The native acid phosphatase complement of hazel seeds had an apparent Mr of 81.5 +/- 3.5 kDa as estimated by size-exclusion chromatography, while the determined pI values were 5.1 (APase1), 6.9 (APase2) and 7.3 (APase3). The optimum pH for p-nitrophenyl phosphate hydrolysis was pH 3 (APase1), pH 5.6 (APase2) and pH 6 (APase3). The hazel isozymes hydrolysed a variety of phosphorylated substrates in a non-specific manner, exhibiting low Km and the highest specificity constant (Vmax/ Km) for pyrophosphate. They were not primary phytases since they could not initiate phytic acid hydrolysis, while APase2 and APase3 had significant phospho-tyrosine phosphatase activity. Inorganic phosphate was a competitive inhibitor, while activity was significantly impaired in the presence of vanadate and fluoride.

Acid Phosphatase↗
PubMed1984

The kinetics of inhibition of human seminal plasma acid phosphatase by sodium fluoride.

Purified human seminal plasma acid phosphatase is inhibited by sodium fluoride and L(+) tartrate and 50% inhibitions (I50) have been obtained at 7.3 X 10(-5) and 3.0 X 10(-4) M concentrations, respectively. By Lineweaver-Burk plot, sodium fluoride shows non-competitive type of inhibition. Ackermann plot indicates that sodium fluoride is a reversible inhibitor of seminal plasma acid phosphatase. On polyacrylamide activity gel electrophoresis and by densitometric scan, a single molecular form of acid phosphatase has been identified in human seminal plasma. Inhibition patterns by sodium fluoride and L(+) tartrate have also been performed by polyacrylamide activity gel electrophoresis and almost complete inhibition of hydrolysis of alpha-napthol phosphate is observed at 20 mM and 100 mM of sodium fluoride and L(+) tartrate, respectively.

Acid Phosphatase↗
PubMed1988

A quantitative cytochemical assay for osteoclast acid phosphatase activity in foetal rat calvaria.

Acid phosphatase activity is prominent in osteoclasts (bone resorbing cells) and has been implicated in the process of bone resorption, although its precise role is not understood. To study the distribution and activity of this enzyme, a quantitative cytochemical method has been developed using undecalcified fresh frozen sections of foetal rat calvariae. Sections were allowed to react with 3 mM naphthol ASBI phosphate at pH 5.0, and the reaction was stopped by rinsing in ice-cold tap water containing 50 mM sodium fluoride. The reaction product was post-coupled to Fast Garnet at 4 degrees C. The absorbance of areas of reaction product in the cytoplasm was measured using scanning and integrating microdensitometry. The initial velocity rate was maintained for up to 2 min at pH 5.0 with a substrate concentration of 3 mM and a section thickness of 5 micron. Under these conditions reaction product was localized to osteoclasts and the surface of bone matrix beneath these cells. Activities in osteoblasts and chondrocytes were negligible. Osteoclastic acid phosphatase was almost totally inhibited by 10 mM fluoride and reduced by 70% by 100 mM tartrate.

Acid Phosphatase↗
PubMed2003

Increase in tartrate-resistant acid phosphatase of bone at the early stage of ascorbic acid deficiency in the ascorbate-requiring Osteogenic Disorder Shionogi (ODS) rat.

The effect of ascorbic acid deficiency on bone metabolism was evaluated using the ascorbate-requiring Osteogenic Disorder Shionogi (ODS) rat model. Ascorbic acid (Asc)-deficient rats gained body weight in a manner similar to Asc-supplemented rats (control) during 3 weeks, but began to lose weight during the 4th week of Asc deficiency. The tartrate-resistant acid phosphatase (TRAP) activity in serum increased to about 2-fold the control value in the rats fed the Asc-free diet for 2, 3, and 4 weeks (AscD2, AscD3, and AscD4), while a decrease in the alkaline phosphatase (ALP) activity was observed only in AscD4 rats. The serum pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) level significantly increased to 1.3-, 1.4-, and 1.9-fold of that in the controls in AscD2, D3, and D4, respectively. The ALP activity in the distal femur was unchanged in AscD1, D2, and D3, but decreased to 50% of the control level in AscD4 rats. The TRAP activity in the distal femur increased to about 2-fold of that in the controls in the AscD2 and D3 and decreased to the control level in the AscD4 rats. The amount of hydroxyproline in the distal femur significantly decreased to about 80%, 70%, and 60% of the control in AscD2, D3, and D4 rats, respectively. These decreases were associated with a similar reduction in the calcium content of the distal femur. Histochemical analysis of the distal femur showed an increase in TRAP-positive cells in AscD2 and AscD3 rats and a decrease in the trabecular bone in AscD2, D3, and D4 rats. These results suggested that a deficiency of Asc stimulated bone resorption at an early stage, followed by a decrease in bone formation in mature ODS rats which already had a well-developed collagen matrix and fully differentiated osteoblasts.

Acid Phosphatase↗
PubMed1980

Radioimmunoassay of bone marrow prostatic acid phosphatase.

The clinical value of prostate acid phosphatase (PAP) measurements in the bone marrow aspirate of patients with prostatic adenocarcinoma has been unclear. Using a radioimmunoassay (RIA) to measure PAP, we have evaluated this potential indicator of occult metastases in 127 controls and in 300 patients with prostatic adenocarcinoma. Elevations of the tumor marker were found in 9%, 10%, 19%, and 82% of patients with stages B, C, D1, and D2 adenocarcinoma respectively. Clinical follow-up ranging from 7 to 43 months (average 23 months) was available for 97 patients without any initial indication of metastasis by bone scan. In this group 11 patients had elevated levels of bone marrow acid phosphatase (BMAP) by RIA and four developed radiological evidence of bone metastasis 21-25 months following initial staging. However, only three of the 86 patients with normal BMAP levels have developed bone metastasis. Our results indicate that measurement of bone marrow PAP by immunological methods has prognostic significance. Dilution of the bone marrow aspirate by peripheral blood, however, may limit the application of this technique.

Acid Phosphatase↗
PubMed2002

Inhibition of human renal acid phosphatases by nephrotoxic micromolar concentrations of fluoride.

Fluoride is considered to be a nephrotoxic substance, due to the association of 50-180 microM serum concentrations of fluoride with dose-related, subclinical to overt clinical renal impairment. At these concentrations the cellular targets of fluoride in renal tissue remain unknown. Fluoride at micromolar concentrations inhibits some enzymes including phosphatases. Here the effects of fluoride on a recently characterized acid phosphatase complex present only in a few human tissues were studied. This enzyme complex consists of alkaline fixation-resistant beta-glycerophosphatase and tartrate-resistant a-naphthyl phosphatase, and these are different from activities of known types of acid phosphatase and specific phosphatases. In kidney, strong activities for this complex are detected only in the endothelium of the afferent arterioles and in glomeruli. It appeared that alkaline fixation-resistant and lysosomal acid phosphatase activities were significantly inhibited in afferent arterioles and glomeruli by 75 microM fluoride. Tartrate-resistant activity was significantly inhibited by greater concentrations (250 microM). Inhibition of acid phosphatases in the afferent arterioles and glomeruli may be one renal target of fluoride nephrotoxicity. Although the physiological substrates of this acid phosphatase complex are unknown, its specific and restricted location may indicate a role in regulation of renal circulation.

Acid Phosphatase↗
PubMed1989

Autonomic control of acid phosphatase exocrine secretion by the rat prostate.

In vivo prostatic secretion was collected from retired breeder Sprague Dawley rats using a method for isolated perfusion of the rat prostatic urethra. Enzymatic acid phosphatase determination was performed on the collected effluent. Control acid phosphatase secretion was 24.2 +/- 2.7 nm over 30 minutes. Intravenous phenylephrine 5 mg/kg stimulated a 10 fold increase in acid phosphatase secretion. The secretion seen with phenylephrine was dose dependent and could be blocked with prazosin, but not yohimbine, atropine, or propranolol. Intravenous beta-adrenergic agonist isoproterenol caused no increase in the secretion of rat prostatic acid phosphatase. Intravenous administration of the cholinergic agonist pilocarpine also resulted in a dose dependent rise in acid phosphatase secretion. The stimulation seen could be blocked by atropine but not phentolamine or propranolol. The stimulation of acid phosphatase secretion seen with alpha 1 adrenergic or cholinergic agonists was not additive. Intravenous vasoactive intestinal peptide did not stimulate acid phosphatase secretion nor did it augment the secretion induced by alpha 1 adrenergic or cholinergic agonists. Release of acid phosphatase into rat prostatic exocrine secretion is under both alpha 1 adrenergic and cholinergic control.

Acid Phosphatase↗