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PubMed1973

Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae.

Saccharomyces cerevisiae strain H-42 seems to have two kinds of acid phosphatase: one which is constitutive and one which is repressible by inorganic phosphate. The constitutive enzyme was significantly unstable to heat inactivation, and its K(m) of 9.1 x 10(-4)m for p-nitrophenylphosphate was higher than that of the repressible enzyme (2.4 x 10(-4)m). The constitutive and the repressible acid phosphatases are specified by the phoC gene and by the phoB, phoD, or phoE gene, respectively. Results of tetrad analysis suggested that the phoC and phoE genes are linked to the lys2 locus on chromosome II. Since both repressible acid and alkaline phosphatases were affected simultaneously in the phoR, phoD, and phoS mutants, it was concluded that these enzymes were under the same regulatory mechanism or that they shared a common polypeptide. The phoR mutant produced acid phosphatase constitutively, and the phoR mutant allele was recessive to its wild-type counterpart. The phoS mutant showed a phenotype similar to that of a mutant defective in one of the phoB, phoD, or phoE genes. However, the results of genetic analysis of the phoS mutant clearly indicated that the phoS gene is not a structural gene for either of the repressible acid and alkaline phosphatases, but is a kind of regulatory gene. According to the proposed model, the phoS gene controls the expression of the phoR gene, and inorganic phosphate would act primarily as an inducer for the formation of the phoR product which represses phosphatase synthesis.

Acid Phosphatase↗
PubMed1996

Acid phosphatase: defining a role in androgen-independent prostate cancer.

OBJECTIVES: In multivariable analysis, post-therapy change in prostate-specific antigen (PSA) was shown to be the most significant factor predictive of survival in patients with androgen-independent prostate cancer. To refine the model, we studied the patterns of change in acid phosphatase, alkaline phosphatase, and lactate dehydrogenase after treatment. METHODS: One hundred seven patients with androgen-independent prostate cancer treated on seven different protocols in Memorial Sloan-Kettering Cancer Center were evaluated. For tumor-specific (acid phosphatase and PSA) and nontumor-specific (alkaline phosphatase and lactate dehydrogenase) enzymes, a minimum 50% or 80% decrease from baseline documented on three separate occasions a minimum of 6 weeks apart was required to categorize a patient as having a decline. RESULTS: Nineteen patients (18%) had either a 50% decline in acid phosphatase or PSA, of whom 13 (68%) had a decline of both markers. Six (32%) patients showed discordance between the two parameters. Declines in PSA level typically preceded declines in acid phosphatase levels. The median survival of patients showing declines in both markers exceeded that of patients showing declines in PSA alone by 1 year. Although baseline measurements of alkaline phosphatase or lactate dehydrogenase did add additional prognostic information, post-therapy changes did not. CONCLUSIONS: Post-therapy declines in PSA and acid phosphatase represent reproducible endpoints for clinical trials in androgen-independent disease. The requirement of a repeated and parallel decline in both markers may improve the results observed by monitoring declines in PSA alone. Monitoring the two parameters may allow the development of models that can be used as surrogate endpoints for response and survival in a disease in which reproducible measurements of response are lacking.

Acid Phosphatase↗
PubMed1971

Effects of dietary copper loading on livers of rats. I. Changes in subcellular acid phosphatases and detection of an additional acid p-nitrophenylphosphatase in the cellular supernatant during copper loading.

Significant changes occurred in lysosomal structure and function as copper was metabolized by rat livers. Hepatic total acid p-nitrophenylphosphatase (pNphiPase) activity was markedly increased in copper-loaded rats, and this increase was almost completely accounted for by heat- and formalin-stable (HFS) acid pNphiPase. Heat- and formalin-labile acid pNphiPase was essentially unchanged. On a subcellular level, the microsomal and supernatant fractions reflected the greatest relative increase in HFS acid pNphiPase. Increases in lysosomal, HFS acid pNphiPase in the large-granule fractions correlated with increase in solubilized large-granule enzymes, LG I, with mol wt > 200,000. LG II, representng solubilized large-granule enzymes with mol wt < 200,000, remained unchanged. Marked increases in supernatant acid pNphiPase were principally accounted for by a sevenfold increase in a supernatant lysosomal-like enzyme, DEAE Pk 1, separated by DEAE cellulose chromatography. An additional enzyme, DEAE Pk 2A', that was hardly or not detectable in normal rats, was consistently demonstrated and increased in copper-loaded rats. Serum HFS acid pNphiPase increased in copper-loaded rats, suggesting that the increased hepatic supernatant acid pNphiPase in part escaped into the circulating fluid. Copper was principally associated with cytoplasmic organelles and was highest in mitochondrial and lysosomal fractions.

Acid Phosphatase↗
PubMed1990

Golgi-mediated post-translational processing of secretory acid phosphatase by Leishmania donovani promastigotes.

Monensin, an inhibitor of Golgi function, was used to investigate the role of this cell compartment in the glycosylation of Leishmania donovani promastigote secretory acid phosphatase (EC 3.1.3.2). Monensin-treated cells demonstrated morphological changes in the Golgi complex and secreted enzyme with an altered electrophoretic mobility: two discrete bands of approximately 95 and 110 kDa were found, as compared to the heterodisperse nature of the enzyme from untreated controls. Chemical deglycosylation by mild acid hydrolysis resulted in a similar effect on the electrophoretic mobility of purified extracellular enzyme. Acid phosphatase was also treated with N-glycosidase F (EC 3.5.1.52) to remove N-linked oligosaccharides. The altered lectin-binding properties of the enzyme after these two treatments demonstrated that an unusual type of galactose-containing acid-labile carbohydrate was present in secretory acid phosphatase in addition to the N-linked oligosaccharides. Further, experiments with 32P-labelled enzyme indicated that phosphodiester bonds were the structural component responsible for the sensitivity of this carbohydrate to mild acid hydrolysis. Cumulatively, these results demonstrated that a novel form of Golgi-mediated posttranslational modification had occurred to the secretory acid phosphatase presumably by the addition of an acid-labile phosphoglycan.

Acid Phosphatase↗
PubMed1984

[Role of prostatic acid phosphatases in the treatment of adenocarcinoma of the prostate].

On the basis of a series of 89 patients with a histologically confirmed adenocarcinoma of the prostate and another population of 89 patients with prostatic hypertrophy, also confirmed histologically, the authors study the sensitivity and specificity of the radio-immunological estimation of prostatic acid phosphatase levels. Comparison is made of the performance of radio-immunological techniques with that of conventional techniques. As a general rule, the sensitivity of the test is very low, since amongst 39% of the prostatic carcinomas studied, the RI acid phosphatase level was below the upper limit of normal fixed at 3.2 ng/ml. By contrast, the degree of specificity is high, since amongst 96% of cases with abnormally high RI acid phosphatase levels, the diagnosis was indeed an adenocarcinoma of the prostate. In terms of stages, sensitivity was found to be nil for minor stages T1 - T2 and of the order of 80% for advanced stages. This confirmed data from the literature. In the absence of bone metastases detectable radiologically or by isotope bone scan, an abnormally high RI acid phosphatase level is predictive of lymph node involvement in 90% of cases. By contrast, under the same conditions of bone investigations, a normal RI acid phosphatase level corresponds in 81% of cases with absence of lymph node involvement and in 19% with limited involvement. In patients with value which are normal or become normal under the influence of treatment, the prognosis is better than if such does not apply. Finally, figures given by radioimmunological estimation are much more specific than those obtained by traditional enzyme estimations.

Acid Phosphatase↗
PubMed1995

Lysosomal origin of the chloragosomes in the chloragogenous tissue of the earthworm Eisenia foetida: cytochemical demonstration of acid phosphatase activity.

The cytochemical localization of the lysosomal marker enzyme acid phosphatase was studied in the chloragogenous tissue of earthworms. The Gomori lead technique and the cerium capture technique were utilized. Both techniques demonstrated the chloragosomal location of this enzyme. Only a small proportion of chloragosomes presented reactivity, which suggests that these organelles are distinctly heterogeneous. The reaction product was localized in the periphery of chloragosomes, suggesting a membrane-bound compartmentalization of acid phosphatase. In addition, degenerating mitochondria and membrane whorls were observed in some chloragosomes, indicating the possibility that these organelles perform autophagosomal functions.

Acid Phosphatase↗
PubMed1985

Identification of the gene appA for the acid phosphatase (pH optimum 2.5) of Escherichia coli.

A strain of Escherichia coli exhibiting reduced activity of the periplasmic enzyme acid phosphoanhydride phosphohydrolase (pH 2.5 acid phosphatase) was isolated. The mutation designated appA1 was located at 22.5 min on the E. coli genetic map. Acid phosphatase purified from an appA- transductant showed less than ten percent of the specific activity of an isogenic appA+ strain. The mutant enzyme was highly thermolabile and its Km for paranitrophenyl phosphate was increased about 20-fold. The mutant protein cross-reacted with antibody to the wild-type enzyme and had the same molecular weight and concentration in extracts as the wild-type enzyme. These findings strongly suggest that appA is the structural gene of the acid phosphatase.

Acid Phosphatase↗
PubMed1981

Molecular properties and active form of nonspecific acid phosphatase from Schizosaccharomyces pombe.

Equilibrium sedimentation experiments of the native acid phosphatase indicate a dimer-tetramer dissociating nonequilibrating system with a dimer Mr = 180,000 g/mol. The hydrolysis of nitrophenylphosphate was used to determine the sedimentation coefficient of the active species. The s20,w value for the species which degrades nitrophenylphosphate is 13.52 +/- 0.46 S in 1% sucrose and 13.72 +/- 0.11 S in 1.3 M sodium chloride, corresponding to the Svedberg value of the tetramer species. Several lines of evidence are presented which, together with previous data, indicate that the Schizosaccharomyces pombe nonspecific acid phosphatase is composed of 4 identical or nearly identical polypeptide chains: a, equilibrium sedimentation analysis of the enzyme in denaturing agents indicates the presence of homogeneous material having Mr = 90,800 g/mol; b, digestion with carboxypeptidase A releases 0.82 mol of tyrosine/monomer molecular weight. Concomitant phosphatase inactivation occurred during the splitting off of the tyrosyl terminal residue. Furthermore, a unique NH2-terminal residue (histidine) was determined.

Acid Phosphatase↗
PubMed1980

[The development of determining human prostatic acid phosphatase by radioimmunoassay (author's transl)].

We purified human prostatic acid phosphatase (hPAP) from prostatic tissues by affinity chromatography, DEAE cellulose and gel filtration and also examined physicochemical properties of highly purified PAP. We developed a double-antibody radioimmunoassay for hPAP in serum, with use of antiserum raised in rabbit against highly purified PAP. The antiserum did not cross react with acid phosphatase from platelets and red blood cells. Experimental detail are outlined to assess the reproducibility and reliability of the method under various conditions. The upper limit of the serum PAP levels in the present assay was set at 3.0 ng/ml by 162 determinations of samples. The serum PAP levels of 2 untreated patients with prostatic carcinoma were higher than 3.0 ng/ml and 39 patients with benign prostatic hyperplasia were an average value of 1.9 ng/ml.

Acid Phosphatase↗
PubMed1991

Regulation and expression of type V (tartrate-resistant) acid phosphatase in human mononuclear phagocytes.

Human type V (tartrate-resistant) acid phosphatase belongs to a unique group of iron-binding proteins that includes uteroferrin and other purple phosphatases. The enzyme is normally restricted to osteoclasts and certain phagocytic cells but its rôle is unknown. We show that phosphatase mRNA is abundant in cells of monohistiocytic phenotype and that enzyme expression in cultured human monocyte-derived macrophages is depressed by gamma-interferon and bacterial lipopolysaccharide, agents that promote functional differentiation in these cells. In contrast, phorbol ester, which stimulates intracellular calcium-mediated events, greatly enhances type V phosphatase expression and mRNA abundance. Lymphokine and phorbol ester-modulated expression of type V acid phosphatase expression thus represents a model system for investigating proliferative responses that are specific to cells of the mononuclear macrophage system.

Acid Phosphatase↗
PubMed1981

Clomiphene citrate administration to normogonadotropic subfertile men: blood hormone changes and activation of acid phosphatase in seminal fluid.

Clomiphene citrate was administered as a 50 mg oral daily dose to 44 normogonadotrophic (serum FSH 2-10 mIU/ml) subfertile men for 3 months. The treatment resulted in significant increases in FSH and LH concentrations, whereas prolactin remained unchanged. Serum testosterone and oestradiol both increased highly significantly. The increased testosterone levels suggest that the elevated LH levels had not led to "down regulation" of Leydig cell LH/hCG receptors, neither had the greatly increased estradiol led to depletion of these receptors. This is suggested to be a result of the blocking of testicular oestradiol receptors by the estrogen antagonist, clomiphene. Sperm count increased highly unchanged. The spermatic fluid concentrations of zinc and magnesium ions were also increased, whereas fructose remained unchanged. The katalytic activity of acid phosphatase in spermatic fluid increased highly significantly, whereas the concentration of the main prostate-specific acid phosphatase, as measured by a specific radioimmunological method, remained unchanged. Therefore, the increased Zn and Mg ion concentrations may be responsible for activation of acid phosphatase (s) in semen, or the treatment led to increased secretion of other prostatic acid phosphatase(s) than the main enzyme. However, it is clear that the secretion of the main prostatic acid phosphatase into semen is under different control than that of Zn++ and Mg++.

Acid Phosphatase↗
PubMed2001

Mice lacking tartrate-resistant acid phosphatase (Acp 5) have disordered macrophage inflammatory responses and reduced clearance of the pathogen, Staphylococcus aureus.

Tartrate-resistant acid phosphatase (TRAP) is a lysosomal di-iron protein of mononuclear phagocytes and osteoclasts. Hitherto, no role for the enzyme in immunity has been identified; however, knockout mice lacking TRAP have a skeletal phenotype caused by an intrinsic osteoclast defect. To investigate a putative function for TRAP in macrophages (Mphi), we investigated proinflammatory responses and systemic microbial clearance in knockout mice compared with age- and gender-matched congenic wild-type mice. Phorbol 12-myristate 13-acetate (PMA)-stimulated and interferon-gamma (IFN-gamma)-induced superoxide formation was enhanced in peritoneal Mphi lacking TRAP; nitrite production in response to stimulation with lipopolysaccharide (LPS) and IFN-gamma was also increased. In addition, secretion of the proinflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta and IL-12, was significantly greater in TRAP-deficient Mphi when stimulated with LPS, with or without addition of either TNF-alpha or IFN-gamma. The activity of tartrate-sensitive (lysosomal) acid phosphatase was increased in Mphi from the knockout mice but activities of the lysosomal hydrolases N-acetyl beta-glucosaminidase and acid beta-glucuronidase were unchanged, indicating selective activation of compensatory acid phosphatase activity. Evidence of impaired Mphi function in vivo was obtained in TRAP knockout mice, which showed delayed clearance of the microbial pathogen, Staphylococcus aureus, after sublethal intraperitoneal inoculation. After microbial challenge, peritoneal exudates obtained from TRAP knockout mice had a reduced population of Mphi. As peritoneal Mphi and neutrophils lacking TRAP were able to phagocytose and kill S. aureus normally in vitro, TRAP may directly or indirectly influence recruitment of Mphi to sites of microbial invasion. Our study shows that TRAP participates in the inflammatory response of the Mphi and influences effector signalling pathways in innate immunity.

Acid Phosphatase↗
PubMed1986

Structure of the transcriptionally repressed phosphate-repressible acid phosphatase gene (PHO5) of Saccharomyces cerevisiae.

We developed a high-copy-number plasmid system containing the entire structural and regulatory sequences of the phosphate-repressible acid phosphatase (PHO5) gene and the TRP1/ARS1 replicator sequences of the yeast Saccharomyces cerevisiae to investigate the mechanism of repression-derepression of transcription. The resulting plasmid was used to transform either wild-type cells or a number of strains which contain mutations in various trans-acting regulatory loci for the production of acid phosphatase. Results of analysis of mRNA levels isolated from the transformed strains grown under repressed or derepressed conditions suggested that normal transcriptional regulation of the gene persisted, although gene copy number was significantly increased. Analysis of changes in linking number (i.e., the number of negative supercoils) of the plasmid isolated under repressed and derepressed growth conditions revealed that the transcriptionally inactive plasmid contained approximately three more negative supercoils than the transcriptionally active plasmid. This difference in topological state was similarly seen in a plasmid containing a sequence-related acid phosphatase gene (PHO11) under the same regulatory control system, but it was not seen in plasmids isolated from some strains containing mutations which caused either fully constitutive or nonderepressible production of acid phosphatase. Finally, analysis of the nucleosome positioning along the inactive gene sequence revealed that an abnormally broad internucleosomal spacer is present in a region presumed to function in the regulation of transcription by the level of Pi in the growth media.

Acid Phosphatase↗
PubMed1992

The internalization signal in the cytoplasmic tail of lysosomal acid phosphatase consists of the hexapeptide PGYRHV.

Lysosomal acid phosphatase (LAP) is rapidly internalized from the cell surface due to a tyrosine-containing internalization signal in its 19 amino acid cytoplasmic tail. Measuring the internalization of a series of LAP cytoplasmic tail truncation and substitution mutants revealed that the N-terminal 12 amino acids of the cytoplasmic tail are sufficient for rapid endocytosis and that the hexapeptide 411-PGYRHV-416 is the tyrosine-containing internalization signal. Truncation and substitution mutants of amino acid residues following Val416 can prevent internalization even though these residues do not belong to the internalization signal. It was shown recently that part of the LAP cytoplasmic tail peptide corresponding to 410-PPGY-413 forms a well-ordered beta turn structure in solution. Two-dimensional NMR spectroscopy of two modified LAP tail peptides, in which the single tyrosine was substituted either by phenylalanine or by alanine, revealed that the tendency to form a beta turn is reduced by 25% in the phenylalanine-containing peptide and by approximately 50% in the alanine-containing mutant peptide. Our results suggest, that in the short cytoplasmic tail of LAP tyrosine is required for stabilization of the right turn and that the aromatic ring system of the tyrosine residue is a contact point to the putative cytoplasmic receptor.

Acid Phosphatase↗
PubMed1994

Interference of body products, food and products from daily life with the modified zinc test and the acid phosphatase test.

The modified qualitative zinc test and the qualitative acid phosphatase test were applied to a total of 1774 semen-free stains made from human body products (n = 575), food products (n = 801), beverages (n = 146), water (n = 120) and other products from daily life (n = 132), in order to assess the degree of interference of these products with the preliminary screening for semen. The zinc test gave positive results in, respectively, 2.4, 3.1, 1.4, 14.1 and 23.5% of the samples, whereas the acid phosphatase test was positive in 3, 3.3, 0, 1.7 and 0% of the samples. Given the large number of positive test results found for products which eventually may be present in stains from alleged sexual assaults, it is concluded that positive screening test results should be interpreted with great caution.

Acid Phosphatase↗
PubMed1982

Comparative study of biochemical technique and radioimmunoassay for the measurement of serum prostatic acid phosphatase. Interest in the diagnosis of prostatic cancer?

The radioimmunoassay of prostatic acid phosphatase and the measurement of L-tartrate labil acid phosphatase by biochemical technique are compared in the diagnosis of prostatic cancer. This study concerning in 122 patients bearing prostatic cancers (40), prostatic adenomas (30) and other solid tumors (52) shows that the sensibility of RIA technique is better than the biochemical one. The positive predictive value of PAP-RIA is 93 p. cent However, seeing that the percentage of positivity of RIA in intracapsular stages rarely exceeds 40 p. cent, this test does not allow to increase detection power of early stages. The RIA technique, if it is better than biochemical method will not be effective as a sole screening tool for prostatic cancer and its principal application consists in the follow-up of the therapy of prostatic cancer.

Acid Phosphatase↗
PubMed1999

The active site of purple acid phosphatase from sweet potatoes (Ipomoea batatas) metal content and spectroscopic characterization.

Purple acid phosphatase from sweet potatoes Ipomoea batatas (spPAP) has been purified to homogeneity and characterized using spectroscopic investigations. Matrix-assisted laser desorption/ionization mass spectrometry analysis revealed a molecular mass of approximately 112 kDa. The metal content was determined by X-ray fluorescence using synchrotron radiation. In contrast to previous studies it is shown that spPAP contains a Fe(III)-Zn(II) center in the active site as previously determined for the purple acid phosphatase from red kidney bean (kbPAP). Moreover, an alignment of the amino acid sequences suggests that the residues involved in metal-binding are identical in both plant PAPs. Tyrosine functions as one of the ligands for the chromophoric Fe(III). Low temperature EPR spectra of spPAP show a signal near g = 4.3, characteristic for high-spin Fe(III) in a rhombic environment. The Tyr-Fe(III) charge transfer transition and the EPR signal are both very sensitive to changes in pH. The pH dependency strongly suggests the presence of an ionizable group with a pKa of 4.7, arising from an aquo ligand coordinated to Fe(III). EPR and UV/visible studies of spPAP in the presence of the inhibitors phosphate or arsenate suggest that both anions bind to Fe(III) in the binuclear center replacing the coordinated water or hydroxide ligand necessary for hydrolysis. The conserved histidine residues of spPAP corresponding to His202 and His296 in kbPAP probably interact in catalysis.

Acid Phosphatase↗
PubMed1996

Phosphotyrosine-protein-phosphatases and human reproduction: an association between low molecular weight acid phosphatase (ACP1) and spontaneous abortion.

ACP1 (low molecular weight acid phosphatase) genetic polymorphism has been studied in 173 women with a history of two or more consecutive spontaneous abortions and in 1508 control subjects, including 482 normal pregnant women. The proportion of carriers of ACP1*C allele (*A/ *C, *B/*C) in women with a history of repeated spontaneous abortion is lower than in normal pregnant women and other control groups. Women with repeated spontaneous abortion show a specific decrease of ACP1 S isoform concentration as compared to normal pregnant women. The other component of ACP1 activity, the F isoform, does not show a significant difference between the two groups. The data suggest that women with ACP1 genotypes showing a high concentration of S isoform are relatively 'protected' against spontaneous abortion. Preliminary analysis of a sample of 352 normal puerperae along with their newborn babies supports this hypothesis.

Abortion, Habitual↗