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Total leukocyte acid phosphatase and its isoenzymes in patients with leukemia.

Leukocyte acid phosphatase and its isoenzyme composition was studied in leukemic patients to determine the specificity of different isoenzymes in leukemic leukocytes. It was found that leukocyte acid phosphatase content is significantly increased in ALL, AML, and CML patients, while CLL patients had decreased levels of acid phosphatase. The distribution and intensity of leukocyte ACP isoenzymes vary in respective leukemic condition. Thus isoenzyme 'O' was predominant in AML and CML, while isoenzymes 1, 2 and 3 predominated in ALL. The lack of predominance of isoenzyme 3 was a feature in CLL patients. It was concluded that the isoenzyme patterns, though promising, presented inconclusive picture for diagnosis purpose and further studies on immunochemical characteristics of these isoenzymes are warranted to ascertain their cell specificity.

Acid Phosphatase↗

Changes of activity of alkaline and acid phosphatase in the rabbit eye in the early phase of alkaline and acid injury.

Rabbit corneas were burned either with 1.0 N sodium hydroxide or 1.0 N hydrochloric acid. Enzyme activities of alkaline and acid phosphatases were examined spectrophotometrically in the homogenates of cornea, iris, aqueous humor and vitreous body. On the 3rd day after alkaline as well as acid burn, a significant decrease of both enzyme activities was produced as compared with untreated animals. A more pronounced change was found in the case of alkaline injuries. With both kinds of caustic agents the decrease of acid phosphatase activity was more striking than that of the alkaline phosphatase. Advantages and shortcomings of biochemical and histochemical enzymatic determinations in experimental ocular inflammations are briefly discussed.

Acid Phosphatase↗

[The effect of testosterone propionate, 5 alpha-dihydrotestosterone and 5 alpha-androstan-3 beta, 17 beta-diol on acid phosphatase activity in the prostate of castrated rats].

The acid phosphatase is studied in the prostate gland of rats. It is shown that 10 days after gonadectomy the activity of acid phosphatase lowered considerably. Administration of testosterone propionate or 5 alpha-dihydrotestosterone to castrated animals restored the enzyme activity whereas 5 alpha-androstan-3 beta,17-diol was not effective. Administration of testosterone propionate with one of its metabolites increased the activity of acid phosphatase in the prostate gland, however to a less extent than with the use of the hormone itself. The lowest activity is detected with the simultaneous application of three androgens.

Acid Phosphatase↗

Acid phosphatase activity demonstrated in the nematodes, Dirofilaria immitis and Angiostrongylus cantonensis with special reference to the characters and distribution.

Acid phosphatase activity was demonstrated in the intact blood nematodes, Dirofilaria immitis and Angiostrongylus cantonensis. Biochemical studies on acid phosphatase, using intact females and whole worm, body-wall and visceral homogenates were undertaken to clarify the characteristics and the distribution of the enzyme. In D. immitis, high acid phosphatase activity was observed at pH 3.8--5.8 and in A. cantonensis, at pH 4.5--6.0. Molybdate, fluoride, copper and zinc ions and L(+)-tartate were effective inhibitors of the enzymes of both parasites while cobalt and magnesium ions and D(-)-tartrate had no noticeable effect on the activity. When the effect of substrate concentration on the phosphatase activity was studied, kinetic curves of Michaelis-Menten type were obtained with the 2 species of intact worms as well as their homogenates. The reproductive organs and body wall of D. immitis showed high total acid phosphatase activity. In A. cantonensis, the majority of the enzyme was localized in the body wall. The activity of intact A. cantonensis expressed as microgram Pi/h/mg dry weight decreased with increase in mean worm weight. The characteristics of the acid phosphatase of the 2 nematodes are compared with those of other parasitic helminths and of acid phosphatase of mammalian origin. The localization of the phosphatase responsible for the hydrolysis of the external substrate has been discussed for D. immitis and A. cantonensis based on results of the kinetics and distribution of the enzyme.

Acid Phosphatase↗

CYTOCHEMICAL LOCALIZATION OF ACID PHOSPHATASES IN EUGLENA GRACILIS.

The localization of induced and constitutive acid phosphatase activity in Euglena was studied by light and electron microscopy, using two different cytochemical methods. Cells grown in high phosphate medium have constitutive acid phosphatase activity in three regions: in the Golgi complex, around the paramylum bodies, and in the peri-reservoir vesicles. Cells that have formed an induced acid phosphatase by exposure to a phosphate-deficient medium have, in addition to the constitutive activity localized exactly as in the uninduced cell, a strong activity in the pellicle. The induced activity is not uniformly distributed over the pellicle, but is localized at the notch of each pellicle complex, near a group of about four fibrils and near a characteristic vesicle of the endoplasmic reticulum. In the cytostome, where fission begins during division, there is an alternation of large and small pellicle complexes, both of which have induced phosphatase activity. A similar alternation is seen over the entire pellicle of dividing cells.

Acid Phosphatase↗

Leishmania donovani: generation of monospecific antibody reagents to soluble acid phosphatase.

Four monoclonal antibodies (McAbs) were generated against the soluble extracellular acid phosphatase (EC 3.1.3.2) (S-AcP) of Leishmania donovani. These were detected in the primary screen using an ELISA with promastigote culture supernatants as antigen. Three of the McAbs demonstrated bound S-AcP from such culture supernatants in an enzyme activity binding assay. All immunoprecipitated metabolically labeled S-AcP but none showed any binding to the promastigote surface by indirect immunofluorescence. Moreover, none reacted with Triton X-100 solubilized plasma membranes by immunoprecipitation or Western blotting. These results demonstrated that the McAbs did not recognize the surface membrane bound acid phosphatase, but were specific for the extracellular soluble enzyme. Further, none of the antibodies immunoprecipitated any of the five human acid phosphatase isozymes or reacted with them in Western blots or the enzyme activity binding assay. Therefore, they are specific for the parasite-derived enzyme. One of these was used to affinity purify sufficient L. donovani S-AcP to immunize a rabbit and generate a specific, polyvalent antiserum. This polyvalent antibody immunoprecipitated S-AcP activity but did not cross-react with the surface membrane acid phosphatase, indicating that these two parasite enzymes are separate gene products.

Acid Phosphatase↗

The role of the radioimmunoassay for prostatic acid phosphatase in prostatic carcinoma.

Considerable controversy exists as to the exact role of prostatic acid phosphatase in the investigation of patients with adenocarcinoma of the prostate. In order to compare different clinical trials, consistent standards of patient selection and staging criteria must be applied on a prospective basis. Other variables which can lead to discrepancies in the results include sources and purification of antigen as well as the analytic accuracy of the immunologic method used. The statistical approach has illustrated the futile outcome of screening an unselected population. On the other hand, if appropriate criteria must be stressed that these estimates have been based on the best possible data available; we have not been able to reproduce either the high sensitivity or specificity reported using three different radioimmunoassays. Therefore, despite the advantages of immunologic methods, we cannot recommend the application of the radioimmunoassay for prostatic acid phosphatase for screening of males for adenocarcinoma of the prostate. At present, no clear explanation can be offered for the elevation of serum prostatic acid phosphatase in patients with apparently localized adenocarcinoma, but it may be of prognostic significance. We have found marked variability in the production of prostatic acid phosphatase by neoplastic acini, and normal levels of prostatic acid phosphatase in patients with metastatic carcinoma may be associated with tumors of limited secretory capacity. Clearly, both the physiologic and methodologic limitations of current radioimmunoassays should be recognized.

Acid Phosphatase↗

Complex segregation analysis for a three-allele locus: experience from an analysis of acid phosphatase activity.

A complex segregation analysis of acid phosphatase activity in 50 British families showed that the essential features of the acid phosphatase polymorphism, i.e., a major gene with three alleles, is retrieved by using the biallelic mixed model. The estimates of gene frequency and displacement obtained from segregation analysis were in agreement with those obtained from electrophoretic studies. In addition, there was evidence for a multifactorial component.

Acid Phosphatase↗

Cloning and characterization of the NapA acid phosphatase/phosphotransferase of Morganella morganii: identification of a new family of bacterial acid-phosphatase-encoding genes.

The gene encoding a minor phosphate-irrepressible acid phosphatase (named NapA) of Morganella morganii was cloned and sequenced, and its product characterized. NapA is a secreted acid phosphatase composed of four 27 kDa polypeptide subunits. The enzyme is active on several organic phosphate monoesters but not on diesters, and is also endowed with transphosphorylating activity from organic phosphoric acid esters to nucleosides and other compounds with free hydroxyl groups. Its activity is inhibited by EDTA, inorganic phosphate, nucleosides and Ca2+, but not by fluoride or tartrate, and is enhanced by Mg2+, Co2+ and Zn2+. At the sequence level, the NapA enzyme did not show similarities to any other sequenced bacterial phosphatases. However, a search for homologous genes in sequence databases allowed identification of two open reading frames located within sequenced regions of the Escherichia coli and Proteus mirabilis genomes respectively, encoding proteins of unknown function which are highly homologous to the Morganella enzyme. Moreover, the properties of the NapA enzyme are very similar to those reported for the periplasmic nonspecific acid phosphatase II of Salmonella typhimurium (for which no sequence data are available). These data point to the existence of a new family of bacterial acid phosphatases, which we propose designating class B bacterial acid phosphatases.

Acid Phosphatase↗

Intracellular acid phosphatase content and ability of different macrophage populations to kill Nocardia asteroides.

It has been reported that the activity of lysosomal acid phosphatase decreases inversely with numbers of ingested virulent Nocardia spp. in normal murine peritoneal and alveolar macrophages. These studies suggested that this relationship correlated with the effectiveness of these macrophage populations in killing Nocardia asteroides. Experiments were designed to determine if acid phosphatase activity is affected by infection with N. asteroides in four different macrophage populations isolated from normal and nocardia-immunized mice. Macrophages were also tested simultaneously for their ability to kill N. asteroides. Peritoneal, alveolar, and splenic macrophages and Kupffer cells were infected in vitro with strains of N. asteroides of differing virulence. Uptake and killing assays were performed. Acid phosphatase levels and numbers of intracellular nocardiae were quantitated in the same macrophages, using a computer-assisted cytophotometry system. Acid phosphatase activity decreased inversely with numbers of intracellular nocardiae in macrophages that could not kill or inhibit this pathogen. Acid phosphatase activity was not significantly changed in macrophages that inhibited growth of, but did not kill, N. asteroides, whereas activity was increased or enhanced in macrophages that killed most of the ingested nocardiae. The order of nocardicidal effectiveness (and resistance to enzyme activity reduction with infection) for normal macrophages was splenic greater than peritoneal greater than alveolar greater than Kupffer. In contrast, the order of these two parameters for macrophages isolated from immunized mice was Kupffer greater than peritoneal greater than alveolar greater than splenic. These results demonstrate that lysosomal acid phosphatase activity is an effective marker of the ability of macrophages to inhibit growth of and kill N. asteroides and that macrophages isolated from different anatomical sites differ functionally from each other with respect to nocardicidal and acid phosphatase activities.

Acid Phosphatase↗

Cytochemical determination of acid phosphatase activity in isolated rat hepatocytes during starvation-induced proteolysis.

Acid phosphatase activity in isolated rat liver parenchymal cells has been investigated with quantitative histochemical means during short-term starvation, which leads to a considerable loss in protein mass in the parenchyma. Animals trained to a meal-feeding regime in which food was available during 1 h only per 24 h (using an automatic food dispensing machine), were sacrificed 6, 12, 18, 24 and 36 h after food had been withheld at the time point (23.00 h) of meal feeding. Acid phosphatase activity was analysed cytophotometrically in isolated hepatocytes incorporated into polyacrylamide gels before the enzyme reaction technique with the post-azo coupling was carried out. No indication could be found for any significant changes in the amount of acid phosphatase activity per individual hepatocyte during the entire period of fasting, as compared with two time points (11.00 and 23.00 h) before the theoretical onset of fasting. It is concluded that the considerable enhancement of protein degradation in the lysosomal apparatus during fasting is not reflected by changes in the cellular acid phosphatase activity.

Acid Phosphatase↗

[Biological profile of tartrate-resistant acid phosphatase as a marker of bone resorption].

Tartrate-resistant serum acid phosphatase was measured in 123 subjects, 80 of which were normal and the rest pathologic, in order to define the profile and value of this parameter as a biological marker of osteoclastic activity. Normal subjects were divided into age groups based on the period where skeletal growth ends (under 20 years), at the age of menopause in women (50 years, between 20 and 50 years) and those over 50 years. There was an increase in tartrate-resistant serum acid phosphatase coinciding with puberty and no sex differences were observed after the 50 year mark, when women showed higher values than men (p less than 0.001). Such tartrate-resistant serum acid phosphatase increase, is reflected as higher values in the 50 year group than in the 20 to 50 year group (p less than 0.001), the only age limit where a negative significant correlation between tartrate-resistant serum acid phosphatase values and age could be observed (p less than 0.05). Values were higher up to the age of 20 years (p less than 0.001) than in any other older age group. Levels increased significantly (p less than 0.001 for both groups) in post-menopausal osteoporosis (n = 20) and in Paget's disease of bone (n = 15), and decreased significantly (p less than 0.05) in imperfect osteogenesis (n = 8), thus revealing its value as a biological marker of osteoclastic activity.

Acid Phosphatase↗

Penicillium chrysogenum extracellular acid phosphatase: purification and biochemical characterization.

An extracellular acid phosphatase (EC 3.1.3.2) from crude culture filtrate of Penicillium chrysogenum was purified to homogeneity using high-performance ion-exchange chromatography and size-exclusion chromatography. SDS-PAGE of the purified enzyme exhibited a single stained band at an Mr of approx. 57,000. The mobility of the native enzyme indicated the Mr to be 50,000, implying that the active form is a monomer. The isoelectric point of the enzyme was estimated to be 6.2 by isoelectric focusing. Like acid phosphatases from several yeasts and fungi the Penicillium enzyme was a glycoprotein. Removal of carbohydrate resulted in a protein band with an Mr of 50,000 as estimated by SDS-PAGE, suggesting that 12% of the mass of the enzyme was carbohydrate. The enzyme was catalytically active at temperatures ranging from 20 degrees C to 65 degrees C with a maximum activity at 60 degrees C and the pH optimum was at 5.5. The Michaelis constant of the enzyme for p-nitrophenyl phosphate was 0.11 mM and it was inhibited competitively by inorganic phosphate (ki = 0.42 mM).

Acid Phosphatase↗

Prostate-specific acid phosphatase: purification and specific antibody production in rabbits.

Demonstration of prostate-specific acid phosphatase by immunologic methods in tissue sections or in plasma necessitates a monospecific antiserum. This is produced by immunizing rabbits with pure prostate-specific acid phosphatase antigen, prepared from seminal fluid. The ejaculate is centrifuged, dialyzed against a citrate buffer, pH 4.8, and centrifuged again. The supernatant is brought onto a Sephacryl S-200 Superfine column and eluted with the same buffer. Prostate-specific acid phosphatase-positive fractions are concentrated, brought onto and stepwise eluted from a Sulphopropyl Sephadex column with citrate buffers at pH 4.8, 5.2, and 5.5. Fractions containing prostate-specific acid phosphatase are concentrated again and purified over a Blue Sepharose CL-6 B column. After elution, a new concentration step yields a protein concentration of 0.5-1.0 mg . ml-1. This sample in polyacrylamide gel electrophoresis shows a single protein band and is used to immunize female rabbits. The purity of the antiserum is then tested by immunoelectrophoresis and an Ouchterlony technic. Besides anti-prostate-specific acid phosphatase, two other antibodies against serum proteins are present, one of which is anti-albumin. Absorption of these impurities results in a monospecific antiserum against prostate-specific acid phosphatase.

Acid Phosphatase↗

Removal of N-glycosylation sites of the yeast acid phosphatase severely affects protein folding.

The influence of N glycosylation on the production of yeast acid phosphatase was studied. A set of synthetic hypoglycosylation mutants was generated by oligonucleotide-directed mutagenesis of the 12 putative sequons (Asn-X-Ser/Thr). Derepression of the hypoglycosylation mutants and analysis of their molecular sizes showed that all 12 sequons of the wild-type acid phosphatase are glycosylated. Activity measurements in combination with pulse-chase experiments revealed that the specific activity was not impaired by the introduced amino acid exchanges. However, absence of N glycosylation severely affected protein folding. Protein folding was found to be the rate-limiting factor in acid phosphatase secretion, and improper folding resulted in irreversible retention of malfolded acid phosphatase in the endoplasmic reticulum. With a decreasing number of attached glycan chains, less active acid phosphatase was secreted. Efficiency of correct folding was shown to be temperature dependent; i.e., lower temperatures could compensate for the reduction in attached oligosaccharides. In addition, protein folding and stability were shown to depend on both the number and the position of the attached oligosaccharides. N glycosylation was found to occur in a process independent of secondary structures, and thus our data support the model of a cotranslocational mechanism of glycosylation.

Acid Phosphatase↗

Acid phosphatase activity: a marker of androgen action in prostate explant cultures.

Acid phosphatase activity in rat ventral prostate explants has been assayed to determine if this parameter could serve as a specific and quantitative marker of androgen action in this in vitro model. Dihydrotestosterone (10 nM) caused an absolute increase in both total (42.5 +/- 2.9 vs control 27.1 +/- 4.0 nmoles p-nitrophenol generated in 30 min/micrograms DNA, P less than .01) and tartrate-resistant acid phosphatase activity (34.1 +/- 1.5 vs control 17.2 +/- 2.8 U/micrograms DNA, P less than .05), and this effect was maximal on the 4th day of culture. This was the time when explant weight and DNA content tended to fall or only to be maintained by androgen. Similar changes were observed with the potent synthetic androgen, mibolerone. The addition of either the antiandrogen cyproterone acetate or flutamide in a 100-fold excess to that of androgen caused significant inhibition in acid phosphatase activity. No significant change was observed at low concentrations of estradiol or progesterone, and only minimal and inconsistent increases in activity were noted at high concentrations. No increase was noted when cortisol, cyproterone acetate, or flutamide was added to the media. We conclude that measurement of acid phosphatase activity in cultured explants of rat ventral prostate provides a biochemical marker of androgenicity that is more specific than measurement of [3H]-thymidine incorporation.

Acid Phosphatase↗

Acid phosphatase in the lysosomal and microsomal fractions of human prostatic epithelium.

Polyacrylamide gel electrophoresis of acid phosphatase from prostatic tissue reveals one more band than seminal plasma. It was attempted to ascertain which subcellular fraction was responsible for that intracellularly localized enzyme. Prostatic epithelium from patients with prostatic hyperplasia was homogenized, and a lysosomal and microsomal fraction were prepared by differential centrifugation. These two fractions were further centrifuged on an isopycnic Percoll gradient. The intracellularly localized form of acid phosphatase was associated with the lysosomal as well as with the microsomal fraction. In a fused rocket electrophoresis experiment these acid phosphatases cross-reacted with antiserum from seminal plasma. After neuraminidase treatment of the acid phosphatase of lysosomal and microsomal origin, only one activity band was found in polyacrylamide gels. It is concluded that only one acid phosphatase protein exists in prostatic epithelium; differences in electrophoretic mobility are caused mainly by different amounts of sialic acid residues, coupled to the same protein backbone.

Acid Phosphatase↗