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Homologous recombination partly restores the secretion defect of underglycosylated acid phosphatase in yeast.

The majority of secreted acid phosphatase in Saccharomyces cerevisiae is encoded by the PH05 gene. The secretion level of this acid phosphatase is directly determined by its level of glycosylation. Consequently, PHO5-11-encoded acid phosphatase which lacks 11 of 12 glycosylation sites is only poorly secreted. We have isolated and characterized both UV- and EMS-induced variants, which are partly able to restore the secretion of acid phosphatase. Our data indicate that the improved secretion is caused by mitotic intrachromosomal recombination between the PHO5-11 allele and the homologous tandemly repeated PHO3 sequences, resulting in the restoration of glycosylation sites in PHO5-11. Two different recombination mechanisms, unequal sister-chromatid exchange and sister-chromatid gene conversion, are responsible for these alterations of the PHO5-11 locus. Thus, recombination between mutant and wild-type sequences are able to restore the ability of mutant yeast cells to secrete acid phosphatase.

Acid Phosphatase↗

Purification and characterization of a protein tyrosine acid phosphatase from boar seminal vesicle glands.

A protein tyrosine phosphatase (PTPase) with acid phosphatase activity was purified (500-fold) from the fluid of boar seminal vesicles. Preparative purification was performed with a 3-step procedure, employing FPLC S-Sepharose Fast Flow, Mono Q and Superdex 75 column. Protein tyrosine acid phosphatase (PTAPase) was homogeneous by polyacrylamide gel electrophoresis (PAGE, SDS-PAGE). PTAPase is a glycoprotein which has a molecular weight of about 41-42 kDa. This enzyme was maximally active at pH 5.5, and its thermostability was less than 80 degrees C. The K(m) value for p-nitrophenylphosphate, a specific synthetic substrate, was 0.87 x 10(-3)M, however, higher substrate specificity was shown when phosphotyrosine (K(m)=0.37 x 10(-3)M) and protein fragments, such as gastrin (K(m)=0.0032 x 10(-3)M) and hirudin (K(m)=0.0075 x 10(-3)M), were used as substrates. Activity of PTAPase was inhibited by dephostatin, molybdate and orthovanadate by 100, 95 and 70%, respectively, when phosphotyrosine was used as the substrate. Immunofluorescence study has shown that the seminal vesicles are the only source of PTAPase in boar seminal plasma.

Acid Phosphatase↗

Isolation of tau-phosphohistidine from a phosphoryl-enzyme intermediate of human prostatic acid phosphatase.

The carbethoxylation of prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) was accompanied by modification of histidine residues and the inactivation of the enzyme. These findings are consistent with photoinactivation experiments described earlier (Rybarska, J. and Ostrowski, W (1974) Acta Biochim, Polon. 21, 377--390). Prostatic acid phosphatase was phosphorylated at alkaline pH using p-nitrophenyl [32P]phosphate as substrate. Phosphoryl enzyme is stable in alkaline solutions and undergoes dephosphorylation at acidic pH. After hydrolysis of phosphoryl enzyme in strong alkaline solution, a single phosphoryl amino acid was isolated from hydrolyzate and identified as the tau-phosphohistidine.

Acid Phosphatase↗

The complete amino acid sequence of the low molecular weight cytosolic acid phosphatase.

This paper presents the complete amino acid sequence of the low molecular weight acid phosphatase from bovine liver. This isoenzyme of the acid phosphatase family is located in the cytosol, is not inhibited by L-(+)-tartrate and fluoride ions, but is inhibited by sulfhydryl reagents. The enzyme consists of 157 amino acid residues, has an acetylated NH2 terminus, and has arginine as the COOH-terminal residue. All 8 half-cystine residues are in the free thiol form. The molecular weight calculated from the sequence is 17,953. The sequence was determined by characterizing the peptides purified by reverse-phase high performance liquid chromatography from tryptic, thermolytic, peptic, Staphylococcus aureus protease, and chymotryptic digests of the carboxymethylated protein. No sequence homologies were found with the two known acylphosphatase isoenzymes or the metalloproteins porcine uteroferrin and purple acid phosphatase from bovine spleen (both of which have acid phosphatase activity). Two half-cystines at or near the active site were identified through the reaction of the enzyme with [14C] iodoacetate in the presence or in the absence of a competitive inhibitor (i.e. inorganic phosphate). Ac-A E Q V T K S V L F V C L G N I C R S P I A E A V F R K L V T D Q N I S D N W V I D S G A V S D W N V G R S P N P R A V S C L R N H G I N T A H K A R Q V T K E D F V T F D Y I L C M D E S N L R D L N R K S N Q V K N C R A K I E L L G S Y D P Q K Q L I I E D P Y Y G N D A D F E T V Y Q Q C V R C C R A F L E K V R-OH.

Acid Phosphatase↗

Acid phosphatase in Gaucher's disease.

Increased acid phosphatase activity in the serum and tissues of patients with Gaucher's disease has now been recognized for two decades, but as yet no relation has been established between the enzyme and the etiology and progress of the disease. Here, we review results obtained by various investigators, ranging from a consideration of the methods used for the evaluation of serum acid phosphatase in Gaucher's disease to the most recent findings regarding the purification and characterization of two acid phosphatase isoenzymes from the spleen from patients with Gaucher's disease. We also discuss the intracellular location of tissue acid phosphatase in patients with Gaucher's disease and its contribution to the increased activity in serum.

Acid Phosphatase↗

Acid phosphatases activity in cheese and starters.

The acid phosphatase activity levels in a number of Greek cheeses and in Cheddar cheeses were found to be unaffected by storage for up to 18 months and 12 months respectively. In Cheddar cheese, starter organisms made an insignificant contribution to this activity. Studies of acid phosphatase prepared from Streptococcus cremoris-lactis NCDO 762 starter cultures showed that the enzyme was of high molecular weight and largely particle-bound. The pH of optimum activity was 5-2 and the enzyme was inhibited by F-minus,Al-3+, a number of heavy metals, oxidizing agents and sulphydryl-modifying reagents. Kinetic measurements at pH 5-2 gave a Km value for p-nitrophenyl phosphate of 1-2 mM. Orthophosphate, pyrophosphate and isoelectrically precipitated casein behaved as competitive inhibitors to the hydrolysis of p-nitrophenyl phosphate with Ki values of 1-2 mM, 1-0 mM, 1-0 MM and 1-1 mM respectively. In spite of this binding to the enzyme, casein provided a very poor substrate for the starter acid phosphatase. The properties of acid phosphatase present in Cheddar cheese made with Str. cremoris NCDO 924 starter were consistent with the enzyme being exclusively of milk origin and small differences between this and the acid phosphatase previously isolated from bovine milk were attributable to the binding of peptides produced during the cheese maturation to the enzyme molecules. It was concluded that in cheese, phosphatase action was due largely to the enzyme of milk origin, with that provided by the starter being of minor importance.

Acid Phosphatase↗

Acid phosphatase isoenzymes in Gaucher's disease.

Acid phosphatase (EC 3.1.3.2) isoenzyme profiles of extracts of splenic tissue and serum from patients with Gaucher's disease were measured by a mini-column ion-exchange chromatographic method [Clin. Chem., 23, 000 (1977)]. Diagnosis of Gaucher's disease in the five patients studied was confirmed by demonstrating decreased (2.3 to 4.1% of normal) glucocerebrosidase activity in the spleen. With p-nitrophenyl phosphate as substrate, increased acid phosphatase activity (three-to eight-fold normal) was demonstrated in spleen tissue from Gaucher;s disease patients; isoenzyme profiles by the ion-exchange column technique showed acid phosphatase isoenzyme 5 to be the predominant isoenzyme. Comparison of acid phosphatase isoenzyme profiles from patients with Gaucher's disease and prostatic carcinoma revealed distinct differences in the activities of isoenzymes 2 and 5. The isoenzyme-5 measurement thus appears to provide a diagnostic test for Gaucher's disease that can be done reapidly and easily in the routine clinical chemistry laboratory.

Acid Phosphatase↗

The use of multifunctional adsorbents to purify membrane-bound phosphatases from Zymomonas mobilis. Purification of acid phosphatase, alkaline phosphatase and ATPase.

The purification of detergent-solubilized membrane-bound phosphatases from Zymomonas mobilis using novel adsorbents is described. The prepared adsorbents have a hydrophobic core with functional groups attached. These functional groups may either increase or decrease the hydrophobicity of the adsorbent, or participate in other forms of interactions. Adsorption of acid phosphatase (ACP), alkaline phosphatase (ALP) and ATPase to these adsorbents was salt-promoted. Desorption was achieved by decreasing the salt concentration or by displacement with increasing concentration of Triton X-100. The results indicate that chromatography on multifunctional adsorbents that are predominantly hydrophobic in character is a procedure that can have a general applicability in purification of membrane proteins.

Acid Phosphatase↗

Glycosylation and secretion of acid phosphatase in Schizosaccharomyces pombe.

We have purified secreted acid phosphatase of Schizosaccharomyces pombe. The enzyme is N-glycosylated, the associated carbohydrate accounts for 90% of the total molecular mass and the protein moiety has a molecular mass of 54 kDa. The deglycosylated enzyme still exhibits enzymatic activity. Using antibodies recognizing the protein moiety of the enzyme we have identified two intracellular precursors of acid phosphatase: an unglycosylated membrane-bound 54-kDa form that accumulates in the presence of tunicamycin and a partially glycosylated 72-kDa form that accumulates mostly in membranes of cells grown in rich medium. We further showed that the conversion of the 54-kDa and 72-kDa forms to partially glycosylated and fully glycosylated acid phosphatase is a regulated process. Growth conditions determine how much of translated 54-kDa acid phosphatase is glycosylated to the 72-kDa form and how much remains unglycosylated in membranes. When cells are grown in a rich medium, 5% of the total acid phosphatase protein remains as unglycosylated enzyme and 8% as partially glycosylated 72-kDa form. In cells grown in the minimal medium, however, all of the 54-kDa and 72-kDa forms of acid phosphatase are rapidly processed to fully glycosylated enzyme. The 72-kDa form and the unglycosylated form of acid phosphatase are not secreted or transported to the plasma membrane.

Acid Phosphatase↗

Heterogeneity of hairy cell tartrate-resistant acid phosphatase.

The human nonerythrocytic acid phosphatases (AcP) are composed of seven distinct activity bands in nondenaturing polyacrylamide gel electrophoresis (PAGE) when stained using either 1-naphthyl phosphate or naphthol ASBI phosphate as substrate. They are numbered 0, 1, 2, 3, 3b, 4, and 5 according to their increasing mobility toward the cathode in acidic conditions. Of these, only the most cationic "band 5" is tartrate resistant (TRAcP). When naphthol ASBI phosphate is used as substrate, AcP activity can also be stained in situ. In the presence of tartrate, activity remains strong in the hairy cells (HC) of hairy cell leukemia (HCL). Thus, the TRAcP stain has remained a reliable marker for HC. To investigate the function of TRAcP in HC, we purified two isoforms of TRAcP from HCL spleen tissue and found them to have similar substrate specificities and inhibitor sensitivities. In this report, we describe in detail the methods for TRAcP purification and compare some of the structural properties of the two isoforms to reinforce the concept that human TRAcP is a heterogeneous group of related enzymes. Band 5 represented only 15-20% of the total TRAcP extracted from HCL spleen. The remaining 80% of TRAcP hydrolyzed p-nitrophenyl phosphate but not naphthol ASBI phosphate and was not detectable in acidic, nondenaturing PAGE gels. Band 5 was solubilized from tissue using 500 mmol/L NaCl after previous extraction with 0.5% (v/v) NP-40 removed most other AcP and TRAcP activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗

Induction of tumor specific cytotoxic T lymphocytes in prostate cancer using prostatic acid phosphatase derived HLA-A2402 binding peptide.

PURPOSE: Human prostatic acid phosphatase is a prostate specific differentiation antigen. Prostatic acid phosphatase levels increase in the serum of patients with prostate cancer and its peptide from positions 299 to 307 (PAP 299-307) is recognized by HLA-A2 restricted cytotoxic T lymphocytes. We investigated whether HLA-A2402 binding prostatic acid phosphatase derived peptides induce HLA-A2402 restricted, tumor specific cytotoxic T lymphocytes from the peripheral blood mononuclear cells of patients with prostate cancer. MATERIALS AND METHODS: Peptide binding activity was measured with RMA-S-A*A2402 cell lines and flow cytometry. Cytotoxic T-lymphocyte activity of the peripheral blood mononuclear cells of patients with prostate cancer and healthy donors was measured by interferon-gamma and (51)creatinine release assays. Prostatic acid phosphatase expression in the tumor cell lines at the messenger RNA and protein levels was investigated by reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively. RESULTS: An HLA-A2402 binding, prostatic acid phosphatase derived peptide consisting of the prostatic acid phosphatase amino acid sequence from positions 213 to 221 (PAP 213-221, LYCESVHNF) showed the ability to induce HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes, which are cytoxic to prostatic acid phosphatase positive tumor cells from the peripheral blood mononuclear cells of patients with prostate cancer. CONCLUSIONS: PAP 213-221 may be appropriate as a cancer vaccine for specific immunotherapy in patients with HLA-A2402 positive prostate cancer.

Acid Phosphatase↗

Purification and properties of two acid phosphatases from midgut glands of abalone Haliotis discus.

Midgut glands of abalone Haliotis discus contained two acid phosphatases [orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2] separable by phosphocellulose column chromatography. They were designated as acid phosphatases I and II in order of elution and were purified 99- and 290-fold, respectively. Purified acid phosphatase II was nearly homogeneous as judged by polyacrylamide gel electrophoresis. The substrate specificity of acid phosphatase I was narrow, whereas that of acid phosphatase II was broad. Good substrates for acid phosphatase I included p-nitrophenyl phosphate, phosphoenolpyruvate, inorganic pyrophosphate, and nucleoside di- and triphosphates. The acid phosphatases did not require any metal ion for maximum activity and were inhibited by Zn2+, Cu2+ and Hg2+. Fluoride and arsenate were potent inhibitors of both enzymes. The pH optima of acid phosphatases I and II were 5.9 and 5.5, respectively. The molecular weights of acid phosphatases I and II were estimated to be 28,000 and 100,000, respectively, by gel filtration on Sephadex G-100. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested that acid phosphatase II consists of two identical subunits.

Acid Phosphatase↗

Effects of 60Co gamma-irradiation of mice on the temporal changes of acid phosphatase activity in spleen and liver.

Acid phosphatase activity and protein content of spleen and liver, and organ weight of whole-body 10 Gy 60Co gamma-irradiated mice were measured every four hours during a 24-hour period. In irradiated mice, in comparison with those non-irradiated, increased acid phosphatase activity in spleen related to both 1 mg of protein at 20.00I, 04.00, 08.00, 12.00, 16.00 and 20.00II and 1 g of fresh tissue at 20.00I, 08.00, 12.00, 16.00 and 20.00II; decreased weight of spleen and protein amount in spleen during the whole 24-hour period, as well as fluctuations in all the parameters measured in spleen, except the level of protein related to 1 g of fresh tissue, were observed. In irradiated mice, compared with the controls, the increased acid phosphatase activity in liver calculated per both 1 mg of protein at 24.00, 08.00 and 16.00 and 1 g of fresh tissue at 08.00 and 16.00; the decreased protein concentration in liver related to 1 g of fresh tissue and the whole organ weight at 12.00, as well as temporal changes in the protein level in liver expressed per 1 g of fresh tissue, were found. 60Co irradiation of mice influenced the acid phosphatase activity and protein concentration in liver are less than in spleen.

Acid Phosphatase↗

Purification and properties of pi-repressible acid phosphatases from Aspergillus nidulans.

Two forms of the pacA-encoded acid phosphatase (designated acid phosphatases I and II) secreted by the mold Aspergillus nidulans grown in low-Pi medium at 37 degrees, pH5.0, were purified to apparent homogeneity by PAGE. The M(r) of the purified enzyme forms were ca 115000 (60000) and 113000 (62000) respectively for forms I and II secreted by strain biA1 and ca 118000 (60000) and 121000 (61000) respectively for forms I and II secreted by strain biA1 pacA1, as determined by exclusion chromatography (number between brackets are the M(r) as determined by SDS-PAGE). All of these purified enzyme forms showed an apparent optimum pH ranging from 6.0 to 6.5 and no deviation from Michaelis kinetics for the hydrolysis of both p-nitrophenylphosphate and alpha-naphthylphosphate. Heat inactivation at 60 degrees and at pH6.0 showed half-lives of 14min (k=0.033min(-1)) and 10min (k=0.069min(-1)), respectively, for the purified acid phosphatases I and II secreted by biA1 strain and half-lives of 0.8min (k=0.92min(-1)) and 0.6min (k=0.95min(-1)), respectively, for the purified forms I and II secreted by the biA1 pacA1 strain. The neutral sugar content of purified acid phosphatases I and II secreted by strain biA1 was 48% and 37% (w/w), respectively, whereas the content of forms I and II secreted by strain biA1 pacA1 was 18% and 11%, respectively.

Journal Article↗

The cytochemistry of tartrate-resistant acid phosphatase. Technical considerations.

Cytochemical demonstration of tartrate-resistant acid phosphatase activity is essential for the diagnosis of leukemic reticuloendotheliosis. In order to perform this test correctly and to interpret the results propertly, it is necessary to understand the technical details of the cytochemical methods thoroughly. The method using naphthol--ASBI phosphoric acid--fast garnet GBC is recommended for this purpose, and factors crucial to the cytochemical study, such as fixation, substrate, coupler, pH and temperature of incubation buffer, counterstains, and mounting media are examined and discussed. Conventional methods for acid phosphatase in the presence and absence of L(+) tartaric acid are also critically examined. The naphthol--ASBI phosphoric acid--fast garnet GBC method is sensitive, technically simple and easily reproducible. Its reaction product is highly chromogenic and is most suitable for cytochemical demonstration of acid phosphatase and tartrate-resistant acid phosphatase activity in cytologic preparations. The naphthol--ASBI phosphoric acid--pararosaniline method is highly specific and is best for histochemical demonstration of acid phosphatase and tartrate-resistant acid phosphatase in tissue sections.

Acid Phosphatase↗

Biosynthesis and processing of lysosomal acid phosphatase in cultured human cells.

The biosynthesis of lysosomal acid phosphatase was studied in a normal human embryonic lung cell line, WI-38. Cells were labeled with radioactive leucine under a variety of conditions, the enzyme was immunoprecipitated using a monospecific antiserum raised against human liver lysosomal acid phosphatase, and the products were separated by electrophoresis and were visualized by fluorography. Lysosomal acid phosphatase constitutes 60% of the total tartrate-inhibitable acid phosphatase in WI-38. It is initially synthesized as a high-molecular-weight precursor polypeptide of 69 kDa. The precursor polypeptide is rapidly glycosylated and processed to a mature enzyme of 53-45 kDa via intermediates of 65 and 60 kDa in WI-38 cells. The 69-kDa precursor polypeptide is also converted to larger precursor polypeptides of 74 and 80 kDa. The multiplicity of precursor polypeptides is due at least in part to differences in the glycosylation and phosphorylation of the polypeptides. Sensitivity of phosphorylated oligosaccharide chains from precursor, mature and small polypeptides to endo-beta-hexosaminidase H-catalyzed cleavage suggests the presence of high-mannose phosphorylated oligosaccharide chains similar to those present on many other lysosomal enzymes. The effects of tunicamycin and ammonium chloride were also studied. In contrast to the effect of ammonium chloride on arylsulfatase A secretion, the lysosomal acid phosphatase in WI-38 cells was not secreted in the presence of NH4Cl. This is consistent with the existence of an alternate route for the transfer of lysosomal acid phosphatase into lysosomes. This alternate route may be the reason that I-cell fibroblasts contain a normal level of lysosomal acid phosphatase.

Acid Phosphatase↗