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At least 1,063 records · Page 59Linked to original sources
PubMed1988

Acid phosphatase activity in the isolated brush border membrane of the tapeworm, Hymenolepis diminuta: partial characterization and differentiation from the alkaline phosphatase activity.

The isolated brush border membrane of the tapeworm, Hymenolepis diminuta, hydrolyzes p-nitrophenyl phosphate over a broad pH range. Acid phosphatase activity (pH optimum at 4.0) is inhibited specifically by sodium dodecyl sulfate (SDS) and NaF, while the alkaline phosphatase activity (pH optimum at 8.8) is inhibited specifically by levamisole, 2-mercaptoethanol, and ethylenediaminetetra-acetate (EDTA). These two phosphatase activities are further differentiated in that (1) there is a rapid decrease in alkaline phosphatase activity when the membrane preparation is incubated at pH 4.0, while there is little loss of acid phosphatase activity, and (2) the alkaline phosphatase activity is solubilized with no loss of activity when the membrane is treated with Triton X-100, while such treatment causes a significant loss of acid phosphatase activity. Both activities are nonspecific and hydrolyze a variety of phosphorylated compounds, but the relative activities of the two phosphatases against these substrates vary significantly.

Acid Phosphatase↗
PubMed1984

Anti-androgens do not alter androgen-dependent characteristics of acid phosphatase in the rat ventral prostate.

When administered to intact adult male rats, cyproterone acetate (10 mg/day), flutamide (15 mg/day), or Compound I (1 mg/day) caused a significant decrease in the organ weight to body weight ratios, with a concomitant rise in the specific activity of prostatic acid phosphatase. These compounds do not affect two other markers of androgen activity in the prostate. Neither the percentage inhibition of acid phosphatase activity by tartrate nor the appearance of the secretory band of acid phosphatase on polyacrylamide gels was altered by the administration of anti-androgens. When administered to castrated rats given doses of 5 alpha-dihydrotestosterone (250-750 micrograms/day), flutamide (15 mg/day) was unable to alter the percentage inhibition of acid phosphatase activity by tartrate, or the pattern of activity on polyacrylamide gels. These results suggest that these anti-androgens affect only some of the androgen-dependent functions of the prostate.

Acid Phosphatase↗
PubMed1975

[Histochemical demonstration of a zinc activated tartrate resistant acid phosphatase in experimentally induced glial microtumors of the rat brain (author's transl)].

The tartrat resistant zinc activated acid phosphatase (ZT-AP) was investigated in 17 glial microtumours of the rat brain. The tumours were induced by N-ethyl-N-nitrosourea injected to newborn rats subcutaneously (85 mg/kg body weight). The morphology of these microtumours corresponds to the statements in the literature. In regard to their behaviour of the investigated enzyme the microtumours may be divided in 2 groups: 1) Microtumours with an activity of acid phosphatases but without any histochemically demonstrable activity of ZT-AP. Histologically they correspond to oligodendric microgliomas. 2) Microtumours with a high activity of acid phosphatases and a remarkable activity of ZT-AP especially in the perivascular cell proliferations. This type corresponds histologically to the astrocytic and mixed glial proliferations including glioblastomas. According to our present findings the ZT-AP was found in astrocytes and especially in mesenchymal cells. In some cases a focal increased activity of ZT-AP could also be observed before histological alterations appeared. We regard it as an early stage of the development of tumours.

Acid Phosphatase↗
PubMed1981

Effect of a transitory ischaemia on the structure-linked latency of rat liver acid phosphatase and beta-galactosidase.

The structure-linked latency of acid phosphatase and beta-galactosidase was studied in rat liver lobes made ischaemic for 1 or 2 h and then recirculated with blood for increasing periods. Free activity of acid phosphatase and unsedimentable activity of beta-galactosidase are increased in homogenates of ischaemic livers. When ischaemia had been maintained for 1 h, the recovery of normal latency for both enzymes was observed 1 h after re-establishment of the blood flow. After a 2 h period of ischaemia, unmasked activity markedly decreases during the first 1 h after restoration of blood flow; after that, a large and irreversible secondary rise takes place. Chlorpromazine, injected 30 min before or just after induction of ischaemia, extensively prevents the latency decrease occurring during restoration of blood flow. Modifications of the hydrolase distribution pattern obtained after differential centrifugation are in agreement with the latency changes. These results suggest that a 2 h ischaemia causes an alteration of the liver lysosomes that is largely reversible and that restoration of blood flow induces an irreversible alteration of these organelles. Chlorpromazine treatment prevents the irreversible lesion from taking place.

Acid Phosphatase↗
PubMed1984

[Cytological study of acid phosphatase activity of plasma cells in monoclonal gammopathies].

The activity of acid phosphatase in bone marrow plasma cells was investigated by a cytochemical method in 12 patients with multiple myeloma, in 12 patients with benign monoclonal gammopathy and in 5 normal controls. The activity of acid phosphatase was significantly higher in the multiple myeloma patients compared with the activity observed in controls and in benign monoclonal gammopathy patients (p less than 0.001). It is therefore suggested that this method may be a valuable adjunct in the differential diagnosis of monoclonal immunoglobulinemias .

Acid Phosphatase↗
PubMed1990

Distribution of acid phosphatase and beta-glucuronidase in the hypoplastic cerebellum of jaundiced Gunn rats. An enzyme histochemical study.

Activities of acid phosphatase and beta-glucuronidase in the cerebella of young jaundiced (j/j) and non-jaundiced (j/+; control) Gunn rats were studied with the enzyme histochemical method. The cerebellum of j/+ rats showed high acid phosphatase activities in Purkinje cells and neurons in the cerebellar nuclei. In j/j rats, a number of neurons were lost and numerous microglialike cells with a high acid phosphatase activity appeared in the hypoplastic cerebellum. Although beta-glucuronidase activity was rarely detected in the control cerebellum, a high enzyme activity was observed associated with microglialike cells in j/j rats. The present results provide a cytological basis for the reported differential increase in the activities of these lysosomal enzymes in the j/j rat cerebellum.

Acid Phosphatase↗
PubMed1965

Changes in fine structure and acid phosphatase localization in rat thyroid cells following thyrotropin administration.

Shortly after the administration of 1/40 unit thyrotropin to rats, 24 hours post-hypophysectomy, the following sequence of changes has been observed within thyroid follicular epithelial cells: (1) the appearance of apical cell surface activity consisting of pseudopods projecting into the follicular lumen; (2) apparent phagocytic engulfment of colloid droplets lacking indications of acid phosphatase activity; (3) close association and probable fusion of newly formed colloid droplets and dense granules, the latter cytochemically positive for acid phosphatase activity; (4) the appearance of presumptive acid phosphatase activity within colloid droplets; and, (5) further colloid droplet changes, viz., basipetal migration and decrease in size, accompanied by an increase in density and in demonstrable acid phosphatase activity. These changes appeared to represent the resorption and degradation of follicular colloid. Comparable results were obtained using intact and more heavily stimulated animals. Colloid biosynthesis was tentatively visualized in these cells as a separate mechanism involving small vesicles prominent in the Golgi region and beneath the apical plasma membrane of some, but not all, thyroid follicular cells in each specimen.

Acid Phosphatase↗
PubMed1980

Clinical significance of serum and bone marrow acid phosphatase.

Currently available immunochemical assays for the determination of serum prostatic acid phosphatase have improved the reliability of this biological marker in carcinoma of the prostate. Although the value of such methods for screening the general population is questionable, a certain percentage of elevated serum levels is observed in patients with localized disease. The significance of such findings is unclear at the present time. Recent evidence suggests that in elevated bone marrow acid phosphatase, using these methods is of predictive value in the future development of metastatic disease.

Acid Phosphatase↗
PubMed1985

Tartrate-resistant acid phosphatase staining of monocytes in Gaucher disease.

Cytochemical studies were performed on peripheral blood from 30 patients with type 1 Gaucher disease. In 29 of the patients, peripheral blood monocytes stained positively for tartrate-resistant acid phosphatase, whereas monocytes from 18 normal individuals and 14 patients with monocytosis did not. In the Gaucher patients, the percentage of monocyte positivity for tartrate-resistant acid phosphatase ranged from 2 to 97. There was no correlation between the percent monocyte staining and the degree of disease severity, as measured by hepatosplenomegaly, pancytopenia, or extent of bone disease, for the group as a whole. In Gaucher patients who had not undergone splenectomy, however, there was a significant correlation between percent monocyte staining and the degree of hepatosplenomegaly, anemia, and thrombocytopenia. The presence of tartrate-resistant acid phosphatase may be secondary to the lysosomal accumulation of glucosyl ceramide within these monocytes, although this remains to be confirmed. If so, these circulating cells may represent precursors of the Gaucher cells in tissues. Tartrate-resistant acid phosphatase staining of peripheral blood monocytes may be useful as a diagnostic marker for Gaucher type 1 disease and for further studies on the pathogenesis of the disease.

Acid Phosphatase↗
PubMed1985

Age-dependent decline of natural killer and antibody-dependent cell mediated cytotoxicity activity of human lymphocytes is connected with decrease of their acid phosphatase activity.

Decline of cytotoxic potential of lymphocytes of aged persons in ADCC and NK cell mediated cytotoxic reaction was paralleled by a drop in the activity of acid phosphatase. Intensity of ADCC reaction and the level of acid phosphatase activity showed statistically significant correlation when these two parameters were measured in peripheral blood of the same persons. The role of acid phosphatase in cytotoxic function of lymphocytes is discussed.

Acid Phosphatase↗
PubMed1992

Correlations between the activities of semen acid phosphatase and Ca(2+)-dependent ATPase and age in different breeds of cocks.

1. The present work aims to find a biochemical criterion for evaluating the evolution of sperm according to age through the study of the ATPase activity from the spermatozoa and the acid phosphatase from the seminal plasma of cocks from three different breeds. 2. The optimal parameters of action of the cock semen acid phosphatase and the Ca(2+)-dependent ATPase from the spermatozoa were studied. 3. The substrate specificity of the semen acid phosphatase and its inhibition by tartrate, fluoride, metavanadate, molybdate and Hg2+ were also studied. 4. The two enzymes were determined from the Sussex, Golden Cornish and Plymouth Rock breeds at different ages. 5. The data lead to the conclusion that some properties of bird spermatozoa are less influenced by breed while the acid phosphatase activity, secreted in the ductus deferens is a breed characteristic.

Acid Phosphatase↗
PubMed1981

Unpredictable fluctuations in serum acid phosphatase activity in prostatic cancer.

Repeated determinations of the elevated serum acid phosphatase activities in five patients with advanced prostatic cancer were found to be highly variable during 24 to 48 hours of observation. Samples collected every three hours had fluctuations of 44% to 97% around the 24- to 48-hour mean values. These fluctuations appeared to be random, had no apparent circadian rhythm, and were unrelated to concurrent medications or activity. These spontaneous variations indicate the need for caution when using serial serum acid phosphatase determinations as an indicator of the response of prostate cancer to therapy. Elevated serum alkaline phosphatase activities did not show these extreme fluctuations.

Acid Phosphatase↗
PubMed1980

Stable acid phosphatase: II. Effects of pH and inhibitors.

Microdensitometry demonstrated that stable acid phosphatase (SAPhase) in rat and hamster osteoclasts, chondroclasts, and chondrocytes has very similar properties. The differences that were observed suggest that conformational alterations in the enzymes may be responsible for inhibition by some agents such as tartrate. These differences in response to inhibitors depend on the method of embedding as well as on species differences. SAPhase appears to correspond to acid nitrophenyl posphatase, as shown by its pH dependent re-activation, resistance to fluoride inhibition at near-neutral pH, and the inverse effect of pH on inhibition by zinc versus aluminium ions. That proportion of SAPhase resistant to fluoride is an acid phosphatase with activity at near-neutral pH rather than a strict neutral phosphatase. The difference between fluoride sensitive and fluoride resistant SAPhase may relate to the varying association of a single enzyme with cell or lysosomal membranes. The close similarity of acid and neutral SAPhase suggests that both may represent a single enzyme in two forms rather than two distinct enzymes.

Acid Phosphatase↗
PubMed1991

Pigeon monocyte/macrophage lysosomes during beta VLDL uptake. Induction of acid phosphatase activity. A model for complex arterial lysosomes.

Lysosomes have long been implicated as a factor contributing to the progression and complication of atherosclerosis. The authors' laboratory previously has shown that lysosomal ultrastructure in arterial macrophage foam cells is altered as primary lysosomes give rise to large pleiomorphic organelles on lipid accumulation during lesion progression. To further explore the subcellular alterations in lysosomes and associated organelles during foam cell formation, three-dimensional (3D) intermediate voltage electron microscopy was used to examine monocyte-derived macrophages (monocyte/macrophages) during early in vitro uptake of beta migrating very-low-density lipoproteins (beta VLDL). Lysosomes were identified using acid phosphatase cytochemistry, and in control cells these organelles constituted 3.5% of the total cytoplasmic volume. Both primary and secondary lysosomes were observed. Upon beta VLDL uptake, the total volume of acid-phosphatase-positive organelles increased threefold over 30 minutes, and the reaction product was found in three additional morphologically distinct structures: tubular lysosomes, membrane stacks, and endoplasmic reticulum with widened cisternae. The proportion of the cell occupied by each of the five acid-phosphatase-positive organelles was quantitated at 10 minutes, 30 minutes, 1 hour, and 4 hours of beta VLDL incubation, and their relative abundance was compared with controls that were processed either with no lipoprotein challenge or albumin incubation for 1 hour. Secondary lysosomes compartment volume peaked at 30 minutes; over the ensuing 3.5 hours, however, the reaction progressively shifted to three new membrane-limited locations. Our observations document the complex 3D organization and spacial relationships among the acid-phosphatase-positive structures induced by lipoprotein uptake. The 3D organization patterns for acid-phosphatase-positive lysosomes in lipoprotein-stimulated pigeon monocyte/macrophages were similar in several aspects to the complex lysosomes previously observed in the macrophages of pigeon arterial lesions.

Acid Phosphatase↗
PubMed1978

[Quantitative shifts in acid phosphatase isoenzymes in the blood in myocardial infarct].

The spectrum of acid phosphatase isoenzymes was studied by means of disk electrophoresis in polyacrylamide gel. Seven isofractions were detected of this enzyme in blood plasma. In patients with the acute stage of myocardial infarction the amount of isofraction 3 was increased, its electrophoretic mobility was 0.479 +/- 0.059. It is suggested to use the test for acid phosphatase fraction 3 in blood plasma as an auxiliary method in the diagnosis of pathological conditions of the myocardium.

Acid Phosphatase↗
PubMed2005

Substrate positioning by His92 is important in catalysis by purple acid phosphatase.

Proteolysis of single polypeptide mammalian purple acid phosphatases (PAPs) results in the loss of an interaction between the loop residue Asp146 and the active site residues Asn91 and/or His92. While Asn91 is a ligand to the divalent metal of the mixed-valent di-iron center, the role of His92 in the catalytic mechanism is unknown. Site-directed mutagenesis of His92 was performed to examine the role of this residue in single polypeptide PAP. Conversion of His92 into Ala, which eliminates polar interactions of this residue with the active site, resulted in a 10-fold decrease in catalytic activity at the optimal pH. Conversely, conversion of this residue into Asn, which cannot function as either a proton donor or acceptor, but can provide hydrogen-bonding interactions, resulted in a three-fold increase in activity at the optimal pH. Both mutant enzymes had more acidic pH optima, with pK(es,1) values consistent with the involvement of an iron(III) hydroxide unit or a hydroxide in the second coordination sphere in catalysis. These results, together with EPR data, support a role of His92 in positioning either the nucleophile or the substrate, rather than directly in acid or base catalysis. The existence of an extensive hydrogen-bonding network that could fine-tune the position of His92 is consistent with this proposal.

Acid Phosphatase↗
PubMed2004

Unfolding and inactivation during thermal denaturation of an enzyme that exhibits phytase and acid phosphatase activities.

The thermostability of an enzyme that exhibits phytase and acid phosphatase activities was studied. Kinetics of inactivation and unfolding during thermal denaturation of the enzyme were compared. The loss of phytase activity on thermal denaturation is most suggestive of a reversible process. As for acid phosphatase activities, an interesting phenomenon was observed; there are two phases in thermal inactivation: when the temperature was between 45 and 50 degrees C, the thermal inactivation could be characterized as an irreversible inactivation which had some residual activity and when the temperature was above 55 degrees C, the thermal inactivation could be characterized as an irreversible process which had no residual activity. The microscopic rate constants for the free enzyme and substrate-enzyme complex were determined by Tsou's method [Adv. Enzymol. Relat. Areas Mol. Biol. 61 (1988) 381]. Fluorescence analyses indicate that when the enzyme was treated at temperatures below 60 degrees C for 60 min, the conformation of the enzyme had no detectable change; when the temperatures were above 60 degrees C, some fluorescence red-shift could be observed with a decrease in emission intensity. The inactivation rates (k(+0)) of free enzymes were faster than those of conformational changes during thermal denaturation at the same temperature. The rapid inactivation and slow conformational changes of phytase during thermal denaturation suggest that inactivation occurs before significant conformational changes of the enzyme, and the active site of this enzyme is situated in a relatively fragile region which makes the active site more flexible than the molecule as a whole.

6-Phytase↗
PubMed1988

Tartrate-resistant acid phosphatase activity in tibial osteoclasts and cells elicited by ectopic bone and suture implants in normal and osteopetrotic rats.

Bone-induced multinucleated cells have been suggested as surrogates for the study of osteoclastic lineage and function. This study evaluates this proposal by comparing acid phosphatase localization in tibial osteoclasts (in situ) with that of cell populations elicited by subcutaneous implantation of devitalized trabecular bone chips from two week old rats and suture into normal and osteopetrotic (ia) rats, emphasizing tartrate-resistant acid phosphatase, an osteoclastic marker. The ia rat mutation of osteopetrosis is characterized by defective osteoclasts which typically express enhanced TRAP activity when compared to normal; ia macrophage populations do not share the same osteoclastic defect and demonstrate normal amounts of acid phosphatase reactivity. The majority of the acid phosphatase activity expressed by implant-elicited mononuclear cells was tartrate sensitive. An increase in the percentage of tartrate-sensitive, but not TRAP-positive, mononuclear cells was observed during the 14-day implantation period, suggesting the mononuclear cells did not undergo osteoclastic differentiation. Both normal and ia osteoclasts contained high concentrations of TRAP reaction product (++) while bone- and suture-induced multinucleated cells examined at 14 days post-implantation were negative (0) or mildly (+) TRAP reactive. We conclude that devitalized bone matrix implanted at this ectopic site is capable of the formation of TRAP-positive (+) multinucleated cells, but when compared on the basis of strength of TRAP activity, the bone-induced multinucleated cells do not resemble active osteoclasts, but are similar to suture-elicited macrophage polykaryons. Therefore, we suggest caution in the use of bone-induced multinucleated cells as surrogates for the study of osteoclasts and normal bone resorption. Instead, these cells may represent a population of cells involved in pathological bone loss due to inflammation.

Acid Phosphatase↗