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PubMed1981

New form of acid phosphatase during lysosome biogenesis.

Lysosome formation was induced in cells of the renal medulla by feeding rats on a K+-deficient diet. The role of the endoplasmic reticulum in the production of acid phosphatase, a typical lysosomal enzyme, was examined. Lysosomal and microsomal fractions were prepared for study by differential centrifugation of homogenates of renal papilla and inner stripe of red medulla. Acid phosphatase activity in the microsomal fraction was distinguished from the activity in the lysosomal fraction in normal tissue by differences in pH optima, tartrate inhibition, distribution of multiple forms after polyacrylamide-gel electrophoresis and detergent-sensitivity. During progressive K+ depletion, acid phosphatase activity in both microsomal and lysosomal fractions of the tissue increased 3-fold. In the lysosomes, K+ depletion was associated with the appearance of a new band of acid phosphatase. The neuraminidase-sensitivity of this band on polyacrylamide-gel electrophoresis indicated that the enzyme protein had been modified by the addition of sialic acid residues. K+ depletion also altered the lysosomal enzyme so that thiol compounds were able to stimulate its activity.

Acid Phosphatase↗
PubMed1995

Studies on the catalytic mechanism of pig purple acid phosphatase.

Several independent experiments failed to reveal any evidence in support of the involvement of a phosphoryl-enzyme intermediate in the catalytic mechanism of pig allantoic fluid purple acid phosphatase: (i) attempts to label enzyme with phosphate derived from [32P]p-nitrophenyl phosphate were unsuccessful; (ii) values of kcat for a series of phosphate derivative varied over a wide range, with the enzyme showing a marked preference for activated ester and anhydride substrates over those with a stable leaving group; (iii) burst titrations revealed a "burst" of p-nitrophenol from p-nitrophenyl phosphate only when the enzyme was added after the substrate, suggesting that this result was an artifact of the order of addition of reagents; (iv) transphosphorylation from p-nitrophenyl phosphate to acceptor alcohols could not be detected, even under conditions where a transphosphorylation to hydrolysis ratio as low as 0.015 could have been measured; (v) enzyme-catalyzed exchange of 180 between phosphate and water was demonstrated, although at a rate much slower than that observed for other phosphatases where the involvement of a phosphoryl-enzyme intermediate in the mechanism has been clearly established. The present results are compared with those obtained in similar studies on other phosphatases, particularly the highly homologous beef spleen purple acid phosphatase, and their implications for the catalytic mechanism of the purple acid phosphatases are discussed.

Acid Phosphatase↗
PubMed2003

Secretion of acid phosphatase in Claviceps purpurea--an ultracytochemical study.

The lead phosphate precipitation method showed the reaction product of acid phosphatase (which reflects the presence of the enzyme glycoprotein) in peripheral cytoplasmic vesicles in the ascomycetous fungus Claviceps purpurea. The product appeared to diffuse from these vesicles (diameter 100-200 nm) towards the cell wall, usually to its sites covered by the capsular fibres exhibiting also acid phosphatase activity. This observation of diffusion of secretory glycoprotein in the cytoplasmic matrix and its orientation to the plasmalemma and capsular fibrils suggests an alternative to the well-described secretory mechanism of transport and exocytosis of glycoproteins via membrane-bound transport conveyors fusing with the cell membrane. It confirms and enlarges our previous finding of the reaction product of acid phosphatase performed by ultrastructural cytochemistry in vacuoles (lysosomes), in the growing cell septum, in cytoplasmic vesicles and in the fibres of the external capsule.

Acid Phosphatase↗
PubMed1974

Lysosomes of the arterial wall. IV. Cytochemical localization of acid phosphatase and catalase in smooth muscle cells and foam cells from rabbit atheromatous aorta.

Cytochemical methods for acid phosphatase and catalase were applied to atheromatous aortas from cholesterol-fed rabbits. Whole tissue, partially digested aortic slices and isolated cells were used for the study. Present in the atheromatous lesions were smooth muscle cells in all stages of foamy transformation, from virtually normal appearing smooth muscle cells to severely altered cells with pronounced lipid accumulation. The results with the acid phosphatase method show that lysosomes increase both in size and in number as the smooth muscle cells become foam cells. In normal appearing smooth muscle cells, acid phosphatase reaction product was found in stacked cisternae of the Golgi apparatus and in small vesicles located in the Golgi region and distributed throughout the cytoplasm. In foam cells, reaction product was found in membrane-limited vacuoles of varying size which typically contained membranous debris or myelin-like figures together with massive lipid deposits. No reaction was seen in "free" cytoplasmic lipid droplets lacking a surrounding membrane. These results confirm and extend previous biochemical findings indicating that, in the cholesterol-fed rabbit, the change from normal smooth muscle cell to foam cell is accompanied by marked physical and chemical changes of the lysosomes, including their progressive overloading with cholesteryl ester. Small diaminobenzidine-positive particles were present in normal smooth muscle cells and in those at all stages of foamy transformation. These particles were more frequent in foam cells, in agreement with the marked increase in catalase activity detected biochemically in these cells.

Acid Phosphatase↗
PubMed2004

Acid phosphatase activity in gerbil prostate: comparative study in male and female during postnatal development.

The prostate is present in both male and female mammals. It is composed of secretory epithelium, connective stroma, smooth muscle and neuroendocrine cells, which are under hormonal regulation. Acid phosphatases catalyze the hydrolysis of orthophosphate monoesters. We have compared the expression of acid phosphatases in gerbil (Meriones unguiculatus) prostate glands in both sexes using young, adult and old animals. Eighteen prostates were isolated, frozen, sectioned, fixed, incubated with sodium beta-glycerophosphate sodium, washed with acetate buffer solution, treated with ammonium sulfide and counterstained with Methyl-Green aqueous solution. Ultracytochemical analyses were also conducted. This substrate revealed total acid phosphatase activity. The expression of the enzyme was heterogeneous, occurring in all ages during postnatal development. The data revealed that the female prostate matured before the male prostate. In addition, acid phosphatase activity in both sexes was regulated by androgen variation concomitant with development.

Acid Phosphatase↗
PubMed1999

A histidine thiol 100 kDa, tetrameric acid phosphatase from lentil, Lens esculenta, seeds with the characteristics of protein tyrosine phosphatases.

A non-specific acid phosphatase (APase) hydrolysing L-tyrosine-O-phosphate and 3'-AMP was purified to electrophoretic homogeneity from mature lentil seeds with apparent native molecular mass of 100 kDa and subunit molecular mass of 24 kDa. These activities appear to reside on the same protein which shows a single band in native and SDS-PAGE. The pH optimum is 5.5, while the K(m) (mM) and V(max) (micromoles/min/mg protein) for p-nitrophenyl phosphate (pNPP) are 0.7 and 9.2 and for L-tyrosine-O-phosphate 1.4 and 10.1, respectively, at 30 degrees C and for 3'-AMP, 2 and 4.4 at 37 degrees C. The protein also hydrolyses other phosphomonoesters to a lesser extent. L-Tyrosine-O-phosphate, 3'-AMP and pNPP hydrolysis is potently inhibited by micromolar orthovanadate and also to nearly the same extent by sodium fluoride, potassium tartrate and metal ions. Histidine and cysteine are likely to be involved in the catalysis. Thermal inactivation studies indicate that the active site conformations for pNPP and 3'-AMP hydrolytic activities are different. The enzyme shows the characteristics of the animal protein tyrosine phosphatase.

Adenosine Monophosphate↗
PubMedDate not supplied

A critical appraisal of the value of vaginal acid phosphatase determination for the estimation of post-coital time.

A careful literature review of the use of vaginal fluid acid phosphatase levels as a means to estimate post-coital time disclosed several inconsistencies. In this study, acid phosphatase levels were determined in vaginal fluid samples obtained from 200 women whose post-coital time was known. No statistical significance (at 5% probability levels) was found when vaginal acid phosphatase levels were correlated with post-coital time.

Acid Phosphatase↗
PubMed2001

Cloning and characterization of a second acid phosphatase from Sinorhizobium meliloti strain 104A14.

Sinorhizobium meliloti has two nonspecific periplasmic acid phosphatases. The NapD enzyme has been previously described, and a second acid phosphatase, NapE, is described in this report. NapE was partially purified from an S. meliloti napD mutant and characterized with respect to molecular mass and substrate range. As predicted from SDS-PAGE analysis, the subunit molecular mass of NapE is approximately 35.8 kDa and gel filtration experiments estimated the native molecular mass to be approximately 70 kDa, indicating that the active enzyme is a homodimer. NapE demonstrated significant activity with p-nitrophenyl phosphate, phenyl phosphate, and alpha-naphthyl-phosphate. The pH optimum was between 4.5 and 5.0. The gene encoding NapE was also sequenced and the inferred amino acid sequence from the predicted ORF was found to be 60% identical and 75% similar to that encoded by napD. An S. meliloti napE mutant was constructed and assessed for symbiotic competence. This mutant did not differ from the wild-type parent strain in nodulation and symbiotic efficiency.

Acid Phosphatase↗
PubMed2003

Crystal structures of human prostatic acid phosphatase in complex with a phosphate ion and alpha-benzylaminobenzylphosphonic acid update the mechanistic picture and offer new insights into inhibitor design.

The X-ray crystal structure of human prostatic acid phosphatase (PAP) in complex with a phosphate ion has been determined at 2.4 A resolution. This structure offers a snapshot of the final intermediate in the catalytic mechanism and does not support the role of Asp 258 as a proton donor in catalysis. A total of eight hydrogen bonds serve to strongly bind the phosphate ion within the active site. Bound PEG molecules from the crystallization matrix have allowed the identification of a channel within the molecule that likely plays a role in molecular recognition and in macromolecular substrate selectivity. Additionally, the structure of PAP in complex with a phosphate derivative, alpha-benzylaminobenzylphosphonic acid, a potent inhibitor (IC(50) = 4 nM), has been determined to 2.9 A resolution. This structure gives new insight into the determinants of binding hydrophobic ligands within the active site and allows us to explain PAP's preference for aromatic substrates.

Acid Phosphatase↗
PubMed1983

Acid phosphatase patterns in microfilariae of Onchocerca volvulus s.l. from the Upper Orinoco Basin, Venezuela.

The patterns of acid phosphatase in strains of Onchocerca volvulus s.l. which parasitize an Amerindian population (Yanomami) in Venezuela's Upper Orinoco Basin were examined by using the naphthol AS-TR phosphate method. The study sample consisted of 40 Yanomami inhabiting a savannah area at 950 m above sea level and 21 Yanomami residents of a tropical rainforest area at an altitude of 250 m. Stained intrauterine microfilariae, still within the egg case, exhibited a diffuse distribution of the enzyme in the early stages of embryonic development and a negative reaction at a more developed stage. Four of the five enzyme staining patterns described by Omar (1978) were found in the 3157 microfilariae examined from skin snips. Their distribution was: Type I--17.2%, Type III--0.5%, Type IV--75.6% and Type V--6.6%. No examples of Type II were observed. The results indicate that acid phosphatase patterns of the Upper Orinoco Onchocerca strain most resemble those of strains from Guatemala and Yemen, and are different from the African strains found in Upper Volta and Liberia. The relative frequency of acid phosphatase patterns was modified by cryopreservation of microfilariae.

Acid Phosphatase↗
PubMed1990

[Histochemical studies of acid phosphatase in the bursa-dependent lymphoid tissue of the spleen of chickens after bursectomy and stimulation with ovine erythrocytes].

The experimental material were female chicks of Tetra SL cross-breed. It was found out that in the spleens of 8-week old chicks, bursectomized in the neonatal period, there occurred not only a decrease in the number of type I and II germinal centres, but also weakening of the reaction to acid phosphatase as well in those organic structures as in periellipsoidal lymphatic tissue. Single administration of sheep red blood cells to the chicks exerted varied effects on the germinal centres in the spleen depending on whether the recipient chicks had or had not been bursectomized. In non-bursectomized chicks there was observed an increase in the number of both types centres as well as intensified in them reaction to acid phosphatase. Now, after administration of the antigen to bursectomized chicks only the number of type II germinal centres was found to have increased with intensified in them reaction to acid phosphatase, while the number of type I centres and intensity of reaction to acid phosphatase stayed almost unchanged, i.e. at the level lowered by bursectomy. On these grounds it may be thought that only type II reproductive centres retain their reactivity to administration of the antigen irrespective of whether the chicks had or had not been bursectomized. Now, the sensitivity of type I centres of the spleen seems to be influenced, first of all, by the biological function of bursa Fabricii. Reactivity similar to that manifested by type I germinal centres, i.e. intensified reaction to acid phosphatase and growth after administration of antigen, was found also in periellipsoidal lymphatic tissue, though, only in non--bursectomized chicks. In the aspect of this research the results obtained constitute the basis for further study of the mechanism of immunological response in chicks.

Acid Phosphatase↗
PubMed2005

[Effects of oxalate on acid phosphatase adsorption and its activity on soil colloids and minerals].

By a batch method, this paper studied the effects of different concentration and pH of oxalate, an important root exudate, on the adsorption of acid phosphatase and its activity on < 2 microm colloids of yellow brown soil and latosol, and on minerals goethite and kaolinite. The results showed that the acid phosphatase adsorption by goethite was less affected by the concentration of oxalate; while the adsorbed amount of this enzyme by the other test colloids and kaolinite was sharply decreased with the increasing oxalate concentration (0-5 mmol x L(-1)) first, and then gradually increased to the level equal to or less than the blank, which may be related to the coordination type of oxalate on soil colloids and minerals, and their surface charge change and dissolution. In the systems oxalate existed, the adsorbed amount of acid phosphatase by soil colloids and minerals decreased in order of goethite >> yellow brown soil > kaolinite > latosol. The pH value for the maximum adsorption of acid phosphatase was between the IEP of the enzyme and the PZC of test colloids and minerals. After the enzyme was immobilized on colloids and minerals, the pH of its maximum specific activity had no change, or shifted to a higher value.

Acid Phosphatase↗
PubMed1979

Multiple forms and glycoprotein nature of acid phosphatase, alpha-fucosidase and alpha-mannosidase of psoriatic scales.

Isoelectric focusing and concanavalin A-Sepharose chromatography were used to study the multiple forms and glycoprotein natures of so-called lysosomal hydrolases from psoriatic scales. Acid phosphatase appeared as 5 different forms with pI values of 6.5, 6.1, 5.8, 5.6 and 5.45. Seven isoenzymes of alpha-fucosidase were identified with pI values of 6.4, 6.2, 5.9, 5.75, 5.65, 5.4 and 5.2. Acid alpha-mannosidase activity appeared as one peak with pI value of 6.75 and a weak activity of neutral alpha-mannosidase was present with pI value of 6.7. Incubation of the extract with neuraminidase increased their pI values of acid phosphatase, alpha-fucosidase and alpha-mannosidase to the more basic forms. This finding suggests that epidermal acid phosphatase, alpha-fucosidase and alpha-mannosidase have some N-acetylneuraminic acid residues. In addition concanavalin A-Sepharose column chromatography was also performed to confirm the glycoprotein nature of acid phosphatase. This enzyme was bound to the column and not released from the column even with the treatment of 0.5 M NaCl, but the enzyme was eluted from the column with the treatment of alpha-methyl-D-glucoside.

Acid Phosphatase↗
PubMedDate not supplied

[Changes in the cAMP levels and acid phosphatase activity in a monolayer primary culture of hepatocytes from newborn rats during anoxia and substrate deprivation].

Acid phosphatase activity and cAMP level were studied in primary hepatocyte culture of new born rats under conditions of anoxia and substrate deprivation (incubation of the cells in Hanks salt solution). Incubation of hepatocytes in Hanks salt solution within one hour under conditions of anoxia caused a significant increase in free (cytosolic) enzyme activity. Substitution of Hanks salt solution by normal tissue culture medium and reoxygenation after 1 hr anoxia resulted in a decrease of free acid phosphatase activity, whereas activity of the enzyme in lysosomal fraction was increased. Content of cAMP was decreased distinctly after 15 min incubation of hepatocyte culture under conditions of anoxia and substrate deprivation and was increased above control values within 5 min of reoxygenation and substitution of Hanks salt solution by normal tissue culture media. Addition of cAMP-containing liposomes to hepatocyte culture under these experimental conditions led to a decrease in free acid phosphatase activity and to an increase of the enzyme activity in lysosomal fraction. cAMP appears to modulate the lability of hepatocyte lysosomal membrane. The mechanisms involved in these processes are discussed.

Acid Phosphatase↗
PubMed1983

The origin of the zymogen granule membrane of the pancreatic acinar cell as examined by ultrastructural cytochemistry of acid phosphatase, thiamine pyrophosphatase, and ATP-diphosphohydrolase activities.

Cytochemical distributions of acid phosphatase, thiamine pyrophosphatase, and ATP-diphosphohydrolase activities have been examined on thin sections of rat pancreas and on isolated zymogen-granule membranes. Acid phosphatase was found in the rigid lamellae separated from the Golgi stacked cisternae, in condensing vacuoles, and in the trans-saccules of Golgi apparatus; it was not detected in purified zymogen-granule membranes. Thiamine pyrophosphatase was detected in trans-saccules of the Golgi apparatus, in purified zymogen-granule membranes, and in the plasmalemma of the acinar cell. It was absent in condensing vacuoles. The ATP-diphosphohydrolase activity has a distribution similar to thiamine pyrophosphatase. These observations illustrate the similarity between the trans-saccules of the Golgi apparatus and the membrane of mature zymogen granules and the disparity between the latter membrane and the membrane of the condensing vacuole. They suggest that the condensing vacuole might not be the immediate precursor of the zymogen granule as commonly assumed. An alternative possibility would be that condensing vacuoles would fuse with the trans-saccule (transition) of the Golgi apparatus which in turn would form mature zymogen granules.

Acid Phosphatase↗
PubMed1985

Cancer serum index and prostatic acid phosphatase for detection of progressive prostatic cancer.

The ratio of alpha 1 acid glycoprotein/prealbumin, referred to as a cancer serum index, has been proposed as a marker for neoplastic disease. In a series of 130 patients with prostate cancer, the cancer serum index was measured along with serum prostatic acid phosphatase. A significant difference for both the cancer serum index and serum prostatic acid phosphatase was detected between those patients with no evidence of active disease after treatment and those with progressive disease after treatment.

Acid Phosphatase↗
PubMedDate not supplied

[Differential diagnosis of allergic and non-allergic dermatitis by measuring the levels of acid phosphatase in neutrophils and peripheral blood lymphocytes].

Using the cytoenzymatic method acid phosphatase was determined in peripheral blood neutrophils and lymphocytes in 25 patients with allergic eczema, 31 patients with eczema due to irritants and 18 clinically healthy subjects. In patients with allergic eczema the percent of neutrophils and lymphocytes containing acid phosphatase was decreased and the activity of this enzyme in neutrophils was reduced. In patients with non allergic eczema these values were normal. The method of determination of acid phosphate in neutrophils and lymphocytes is regarded as useful for the differentiation between both types of eczema.

Acid Phosphatase↗
PubMed1983

Influence of bilirubin on the determination of acid phosphatase in serum.

Bilirubin interferes greatly in the continuous measurement of acid phosphatase, using alpha-naphthyl phosphate as substrate and diazotized 2-amino-5-chlorotoluene (Fast Red TR) as the colorimetric reagent. Fast Red TR and the so-called "direct" (but not "indirect") bilirubin form a coloured azo-compound which absorbs light above 480 nm. Negative absorbance changes are observed at 405 nm, which is used in the determination of acid phosphatase. This leads to apparently negative activities.

Acid Phosphatase↗