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PubMed2005

Structure-function relationships of purple acid phosphatase from red kidney beans based on heterologously expressed mutants.

Purple acid phosphatases are binuclear metalloenzymes, which catalyze the conversion of orthophosphoric monoesters to alcohol and orthophosphate. The enzyme from red kidney beans is characterized with a Fe(III)-Zn(II) active center. So far, the reaction mechanisms postulated for PAPs assume the essentiality of two amino acids, residing near the bimetallic active site. Based on the amino acid sequence of kidney bean PAP (kbPAP), residues H296 and H202 are believed to be essential for catalytic function of the enzyme. In the present study, the role of residue H202 has been elucidated. Mutants H202A and H202R were prepared by site-directed mutagenesis and expressed in baculovirus-infected insect cells. Based on kinetic studies, residue H202 is assumed to play a role in stabilizing the transition state, particularly in charge compensation, steric positioning of the substrate, and facilitating the release of the product by protonating the substrate leaving groups. The study confirmed the essentiality and elucidates the functional role of H202 in the catalytic mechanism of kbPAP.

Acid Phosphatase↗
PubMed2000

beta-Adrenergic receptor manipulation and acid phosphatase and zinc levels in the ventral prostate of the adult rat.

The influence of 15-day treatments with the beta-adrenergic receptor agonist isoproterenol (120 micrograms/kg/d) or the antagonist propranolol (1.00 mg/kg/d) on acid phosphatase and zinc levels in the ventral prostate was examined in intact rats, rats simultaneously injected with dexamethasone (0.25 mg/kg/d) and animals chemically castrated with a single dose of ethane dimethanesulphonate (75 mg/kg). Isoproterenol-treatment significantly increased acid phosphatase concentration in the ventral prostate of intact rats, whereas propranolol prevented a glandular zinc loss induced by dexamethasone administration. These results demonstrate that the levels of both biochemical parameters in the prostate can be altered by beta-adrenergic receptor manipulation. The responsiveness of the two secretory processes is different and depends on the functional status of the ventral prostate.

Acid Phosphatase↗
PubMed1998

[Tartrate-resistant acid phosphatases (TRAP) and cytology of pseudosynovial membranes].

Pseudo-synovial membranes are found at the interface between bone and aseptically lost prostheses. They are supposed to be due to the release of material debris at the interface with bone. They are mostly composed of macrophages and giant cells, and some fibrocytes in the deep layer of the membrane. The different histological structures present in these membranes have been largely described. Very recently, Kadoya et al. have demonstrated that a lot of giant cells present in the pseudo-synovial membranes show a tartrate resistant acid phosphatase activity in the presence of more than 100 mM tartrate. They have also shown that some of these cells were responsible for bone degradation. We have studied the tartrate acid phosphatase activity of a series of 10 membranes containing various material debris: titanium alloy, stainless steel, polymethylmethacrylate, polyethylene. Many mono or multinucleated cells showed a TRAP activity in their lysosomes in the presence of a 400 mM tartrate concentration. In certain membranes, these cells showed a TRAP activity located in the nucleus. This study shows that the macrophage population is very heterogeneous and the difference between osteoclasts and giant cells may be unclear.

Acid Phosphatase↗
PubMed1976

Repression of the acid phosphatase of Saccharomyces bisporus in relation to the polyphosphate content of the cells.

The relationship between the level of stored polyphosphate in growing cells of Saccharomyces bisporus and the repressing or derepression of the synthesis of the enzyme acid phosphatase (EC 3.1.3.2) was investigated. Time-course studies showed that there is no correlation between the cellular concentrations of either polyphosphate or orthophosphate and the ability of the cells to form this enzyme. The only compound investigated that was capable of repressing acid phosphatase synthesis was orthophosphate in the growth medium (i.e. orthophosphate outside the cell).

Acid Phosphatase↗
PubMed1988

Comparative experimental study of the serum prostate specific antigen and prostatic acid phosphatase in serially transplantable human prostatic carcinoma lines in nude mice.

Three different human lines of prostate carcinoma were successively transplanted on Balb/c nude mice and the serum values of the prostate specific antigen (PSA) and prostatic acid phosphatase (PAP) were determined simultaneously. In a group of the tumor-bearing animals the influence of endocrine manipulation (castration, estradiol) on the serum concentration of these tumor markers was studied. As far as untreated tumor-bearing mice are concerned, the serum values of both PAP and PSA proved to be strictly dependent on the tumor volume measured. In the exponential growth phase of the grafted tumors, linear growth was linked with a correspondingly increasing PAP and PSA serum level of the test animals. A close correlation was found to exist between the two tumor markers; however, the indicator value of PSA was 20 to 50 times higher than that of PAP under the test conditions. PSA determination yielded no false-negative results, if PAP was elevated. PAP determination was false-negative in 21 per cent of cases with measurable tumors, although the serum level of PSA already showed marked elevation. In treated animals both markers were found to decrease. Arrested growth and tumor regression was associated with falling PAP and PSA serum levels or with levels within normal range. The results of this experimental study support the conclusion that prostate specific antigen represents a substantially more sensitive tumor marker than prostatic acid phosphatase.

Acid Phosphatase↗
PubMed1994

A recombinant bisphosphoglycerate mutase variant with acid phosphatase homology degrades 2,3-diphosphoglycerate.

To date no definite and undisputed treatment has been found for sickle cell anemia, which is characterized by polymerization of a deoxygenated hemoglobin mutant (HbS) giving rise to deformed erythrocytes and vasoocclusive complications. Since the erythrocyte glycerate 2,3-bisphosphate (2,3-DPG) has been shown to facilitate this polymerization, one therapeutic approach would be to decrease the intraerythrocytic level of 2,3-DPG by increasing the phosphatase activity of the bisphosphoglycerate mutase (BPGM; 3-phospho-D-glycerate 1,2-phosphomutase, EC 5.4.2.4). For this purpose, we have investigated the role of Gly-13, which is located in the active site sequence Arg9-His10-Gly11-Glu12-Gly13 in human BPGM. This sequence is similar to the Arg-His-Gly-Xaa-Arg* sequence of the distantly related acid phosphatases, which catalyze as BPGM similar phosphoryl transfers but to a greater extent. We hypothesized that the conserved Arg* residue in acid phosphatase sequences facilitates the phosphoryl transfer. Consequently, in human BPGM, we replaced by site-directed mutagenesis the corresponding amino acid residue Gly13 with an Arg or a Lys. In another experiment, we replaced Gly13 with Ser, the amino acid present at the corresponding position of the homologous yeast phosphoglycerate mutase (D-phosphoglycerate 2,3-phosphomutase, EC 5.4.2.1). Mutation of Gly13 to Ser did not modify the synthase activity, whereas the mutase and the phosphatase were 2-fold increased or decreased, respectively. However, replacing Gly13 with Arg enhanced phosphatase activity 28.6-fold, whereas synthase and mutase activities were 10-fold decreased. The presence of a Lys in position 13 gave rise to a smaller increase in phosphatase activity (6.5-fold) but an identical decrease in synthase and mutase activities. Taken together these results support the hypothesis that a positively charged amino acid residue in position 13, especially Arg, greatly activates the phosphoryl transfer to water. These results also provide elements for locating the conserved Arg* residue in the active site of acid phosphatases and facilitating the phosphoryl transfer. The implications for genetic therapy of sickle cell disease are discussed.

2,3-Diphosphoglycerate↗
PubMed1975

Demonstration of acid phosphatase activity in the proventriculus of common weaver bird, Ploceus philippinus and whitebreasted kingfisher, Halcyon smyrnensis.

Acid phosphatase activity was histochemically localized in the proventriculus of two birds namely Ploceus philippinus and Halcyon smyrnensis. It was found that acid phosphatase-rich lysosomal activity appears to be relatively better developed in the proventriculus of piscivorous form, H. smyrnensis than that of granivorous form. P. philippinus. Simultaneously, a possible correlationship between the variable lysosomal activity and specific food diets of the birds has been discussed.

Acid Phosphatase↗
PubMedDate not supplied

[Isoenzyme spectrum of lactate dehydrogenase, malate dehydrogenase, esterase and acid phosphatase of rat brain cells at different times after external 1 Gy gamma irradiation].

The influence of external single gamma-irradiation with a dose of 1 Gy on the isoenzyme composition of lactate dehydrogenase, malate dehydrogenase, esterase and acid phosphatase in the cytoplasm of rat brain cells has been investigated. Irradiation was shown to cause differently directed changes in the ratio of the isoenzymes under study at different times after exposure. The isoenzyme spectrum of lactate dehydrogenase and malate dehydrogenase was shown to be normalized on day 30 after irradiation, whereas the isoform composition of esterase and acid phosphatase was not stabilized at that time.

Acid Phosphatase↗
PubMed1980

A closer look at serum prostatic acid phosphatase as screening test.

Radioimmunoassay techniques for the detection of serum acid phosphatase are reported to provide substantial improvement in test sensitivity and test specificity. Calculation of the positive predictive value for this assay, however, does not support its use as a screening modality. Indiscriminate use of this test may have serious medical, psychological, and economic ramifications.

Acid Phosphatase↗
PubMed1977

[Demonstration of osteoclastic acid phosphatase in the serum of patients with giant cell tumors. Preliminary study].

Starting from the fact that an ultrastructural cytochemical study of the Giant-Cell Tumour demonstrated the presence of a large amount of lysosomic acid phosphatase in the tumour cells, an attempt was made to evidence the presence of this enzyme in the serum of patients bearing such a type of bone tumor. Acrylamide gel electrophoresis of the serum allowed one to separate a number of isoenzyme with acid phosphatase activity and to characterize at least two bands different from those secreted by prostate, blood platelets, liver or spleen. The comparison between zymograms of normal and pathological sera, more particularly in Paget disease, led to consider that these two bands had an osteoclastic origin. Besides, these bands vanish after tumor eradication. Acrylamide gel electrophoresis of serum provides therefore a means to support the preoperative diagnosis of Giant-Cell Tumor and, eventually, to detect an early recurrence of the disease.

Acid Phosphatase↗
PubMed2002

Continuous monitoring of prostatic acid phosphatase using self-indicating substrates.

BACKGROUND: The continuous measurement of acid phosphatase (EC 3.1.3.2) activity in serum represents an analytical task not yet sufficiently accomplished. METHODS: Introducing two novel substrates-2-chloro-4-nitrophenyl phosphate (CNP-P), which was preferred, and 4-nitronaphthyl-1-phosphate (NN-P)-an alternative assay to measure enzymatic activity was developed and compared with a modification of Hillmann's method (azo coupling of released naphth-1-ol with a diazonium compound). Apart from different substrate concentrations of 2-chloro-4-nitrophenyl phosphate, 4 mmol/l, and naphthyl-1-phosphate (N-P), 8 mmol/l (with Fast Red TR, 5 mmol/l), respectively, following identical conditions were selected: Citrate, 50 mmol/l, pH 5.75; pentane-1,5-diol, 150 mmol/l; tartrate, 60 mmol/l; 37 degrees C. RESULTS: Whereas intensity and stability of the azo dye unpredictably depend on the albumin concentration of the sample, the direct test with 2-chloro-4-nitrophenyl phosphate resisted sample interferences, showed no intrinsic hydrolysis by albumin, relied on stable reagents and proved superior in sensitivity, precision and ease of handling. In measuring prostatic phosphatase, the proposed procedure closely correlated with Hillmann's method. The preliminary 0.95-reference intervals for adults were 1.2-3.9 kU/l and 5.8-14.8 U/l for total activity, respectively. CONCLUSIONS: The direct assay of the enzyme is suited as an economic, rapid and robust method for mechanized or manual use.

Acid Phosphatase↗
PubMed1997

Bovine kidney low molecular weight acid phosphatase: FMN-dependent kinetics.

A low molecular weight bovine kidney acid phosphatase, electrophoretically homogeneous and with a relative molecular mass of 17.8 kDa, was used in this work. Among the various substrates tested, FMN was found to be the most effective, at pH 7.0. Distinct activation energy values were obtained for p-nitrophenyl phosphate- (45.44 kJ mol-1) and flavin mononucleotide- (28.60 kJ mol-1) hydrolysis reactions. The FMN hydrolysis was strongly inhibited by Cu2 and pCMB, but activated by guanosine. Pyridoxal-phosphate and vanadate were competitive inhibitors for the FMN-dependent reaction.

Acid Phosphatase↗
PubMed1999

Crystal structure of Aspergillus niger pH 2.5 acid phosphatase at 2. 4 A resolution.

The crystal structure of Aspergillus niger pH 2.5 acid phosphatase (EC 3.1.3.2) has been determined at 2.4 A resolution. In the crystal, two dimers form a tetramer in which the active sites are easily accessible to substrates. The main contacts in the dimer come from the N termini, each lying on the surface of the neighbouring molecule. The monomer consists of two domains, with the active site located at their interface. The active site has a highly conserved catalytic center and a charge distribution, which explains the highly acidic pH optimum and the broad substrate specificity of the enzyme.

Acid Phosphatase↗
PubMed1980

Diagnosis of hairy-cell leukaemia by tartrate-resistant acid phosphatase activity in paraffin-embedded tissue sections.

Tartrate-resistant acid phosphatase activity may be demonstrated in paraffin-embedded liver and spleen specimens as well as in decalcified bone marrow biopsies after fixation in a mixed glutaraldehyde-formaldehyde-calcium acetate solution. This technique may routinely be applied to haematologically relevant material and aids in the differential diagnosis of hairy-cell leukaemia.

Acid Phosphatase↗
PubMed1982

Ultrastructural localization of phosphatases in the testes of the domestic fowl: acid phosphatase and thiamine pyrophosphatase.

ACPase and TPPase activity has been examined in the germinal epithelium of the testes in the domestic fowl. ACPase activity in spermatogonia and spermatocytes was confined to the Golgi complex. In spermatids ACPase activity was seen in the endoplasmic reticulum and nuclear envelope in the phase I and especially in the phase II (the elongating phase). This activity gradually decreased during the next phase III (the elongating phase). This activity gradually decreased during the next phase III, and had disappeared in the final phase IV. The membrane body showed ACPase reaction in the small peripheral vacuoles and cisternal structures surrounding large central vacuoles. ACPase was also present in vesicles surrounding the developing tail. Late spermatids showed an abundance of autophagic vacuoles which had a complex array of ACPase positive delimiting membranes. In Sertoli cells ACPase activity was predominant in the lysosomes. TPPase activity was seen in the cisternae of the Golgi complex in spermatogonia and spermatocytes. In spermatids activity was present in the endoplasmic reticulum during the phase II, but it is lost in later stages. The smaller vacuoles and cisternal structures in the membrane body also showed reaction products. According to the present results it is thought likely that the smaller vacuoles and cisternal structures of the membrane body are of endoplasmic reticulum origin. The autophagic vacuoles in spermatids and the lysosomes of Sertoli cells are considered responsible for the degradation of residual bodies cast off by spermatids.

Acid Phosphatase↗
PubMed1993

Early ultrastructural studies on local acid phosphatase activity in rat sciatic nerve after nerve crush.

Rat sciatic nerve was crushed at mid thigh level. 30 minutes up to 24 hours after the lesion, the nerve was excised, fixed, stained for acid phosphatase activity, and embedded in araldite. The nerve was cut lengthwise over a distance of 6 mm proximally and distally to the lesion and examined by electron microscopy. Not more than 30 minutes after damage fundamental changes were found to take place, with little difference between the proximal and the distal "stump". Changes affect the axon itself, the axolemma and the Schwann cell. In the axoplasm, structures not existent in normal axons became visible during the first hour. Acid phosphatase activity appeared in the endoplasmatic reticulum, vesicles and cisterns, along the axolemma, and in the Schwann cell. Enzyme filled vesicles were released from the Schwann cell into the axoplasm. Mitochondria were found in increasing numbers in the axoplasm next to the lesion, being mainly small and round in shape and prominent where various organelles and enzymes had accumulated. It is concluded that the axon itself is capable of enzyme activation and organelle production, and that there is a complex interaction between the Schwann cell and the axoplasm after nerve crush.

Acid Phosphatase↗
PubMed1983

Physiological control of repressible acid phosphatase gene transcripts in Saccharomyces cerevisiae.

We have examined the regulation of repressible acid phosphatase (APase; orthophosphoric-monoester phosphohydrolase [acid optimum], EC 3.1.3.2) in Saccharomyces cerevisiae at the physiological and molecular levels, through a series of repression and derepression experiments. We demonstrated that APase synthesis is tightly regulated throughout the growth phase and is influenced by exogenous and endogenous Pi pools. During growth in a nonlimiting Pi medium, APase is repressed. When external Pi becomes limiting, there is a biphasic appearance of APase mRNA and enzyme. Our data on APase mRNA half-lives and on the flux of intracellular Pi and polyphosphate during derepression are consistent with a mechanism of transcriptional autoregulation for the biphasic appearance of APase mRNA. Accordingly, preculture concentrations of Pi control the level of corepressor generated from intracellular polyphosphate degradation. When cells are fully derepressed, APase mRNA levels are constant, and the maximal linear accumulation rate of APase is observed. A scheme to integrate phosphorus metabolism and phosphatase regulation in S. cerevisiae is proposed.

Acid Phosphatase↗