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Plasma cell acid phosphatase as an adjunct in the differential diagnosis of monoclonal immunoglobulinemias.

Plasma cell acid phosphatase has been studied in 51 patients, 30 of whom were affected with multiple myeloma (MM) and 21 with nonmyelomatous monoclonal immunoglobulinemias (NMMI). Scoring of results displayed a highly significant difference between the median of the MM and NMMI group (343 vs. 204). The use of plasma cell acid phosphatase as a further criterion in the differential diagnosis of monoclonal immunoglobulinemiasis emphasized.

Acid Phosphatase↗

Comparative examination of three radioimmunoassay kits for human prostatic acid phosphatase.

Three commercial radioimmunoassay kits for prostatic acid phosphatase (PAP) were compared on the basis of their ability to measure the enzyme in normal male sera. These kits, issued by Eiken ICL (EIK), Clinical Assays (CLA), and Mallinckrodt (MKT), could measure the serum samples containing PAP above normal levels with precision and reproducibility, and showed excellent linearity on the dilution tests and good correlation with the enzymatic activity. PAP in the serum did not lose immunoreactivity for two weeks if stored below 4 degrees C. However, the sensitivity of CLA and MKT kits should be improved to give reliable values for normal sera with lower PAP contents (less than 1 ng/ml). The upper mean + 2 SD normal limits in ng/ml obtained with these kits were 2.2 (MKT), 2.5 (EIK), and 2.8 (CLA). Some differences in the purity of the standard preparations among these kits were also found. These kits gave different assays values for PAP control sera from CLA and multipurpose QC-RIA sera from Eiken ICL.

Acid Phosphatase↗

Acid phosphatase activity in yolk droplets of chick notochordal cells.

The fine localization of acid phosphatase activity in yolk droplets in the notochordal cells of the developing chick (stage 12-13) has been investigated by electron microscopy. The enzyme reaction products are mainly found on the peripheries of yolk droplets of various different sizes, which are often clustered together to form larger masses. The rough endoplasmic reticulum and Golgi complexes with the substantial or small amounts of reaction product are closely, and occasionally directly, associated with the yolk droplets and their masses. These findings strongly suggested that both the rough and endoplasmic reticulum and Golgi complexes supply the acid phosphatase for the utilization of yolk in the differentiating notochordal cells.

Acid Phosphatase↗

Analysis of isoenzyme patterns of acid phosphatase in acute leukemias.

The status of acid phosphatase isoenzymes was evaluated in cells of patients with acute lymphocytic leukemias or lymphomas by analytical isoelectric focusing in polyacrylamide gels (IEF) on horizontal thin-layer slabs. The isoenzyme patterns were correlated with routine immunological cell surface markers and the relationship of enzyme activity to specific immunological subclasses of ALL is discussed. By isoelectric focusing up to five isoenzyme groups (I-V) containing several isoenzyme were observed. No leukemia specific or additional isoenzyme could be demonstrated. This biochemical characterization showed a marked heterogeneity within two major immunologic subgroups indicating that various differentiation stages of cell maturation could be involved in cALL and T-ALL. According to their degree of maturation along T-cell differentiation axis the leukemic cells displayed no enzyme activity, weak isoenzyme bands or the incomplete or complete isoenzyme pattern seen with normal lymphocytes from human tonsils which were used as controls. The investigation of specific enzymatic patterns can lead to a further definition of subsets of acute leukemias and give insight into lymphopoietic differentiation.

Acid Phosphatase↗

Isolation of a cDNA encoding human lysophosphatidic acid phosphatase that is involved in the regulation of mitochondrial lipid biosynthesis.

In this study, we isolated cDNA encoding lysophosphatidic acid (LPA) phosphatase (LPAP). The amino acid sequence deduced from the cDNA encoding LPAP had 421 residues including a putative signal peptide and was homologous to acid phosphatase, especially at the active site. Human LPAP had 28.5% amino acid identity to human prostatic acid phosphatase. Northern blot analysis showed a ubiquitous expression of LPAP, which was marked in kidney, heart, small intestine, muscle, and liver. Human chromosome map obtained by fluorescence in situ hybridazation showed that the gene for LPAP was localized to chromosome 1 q21. The mutant in which histidine was replaced with alanine at the active site and the putative signal peptide-deleted LPAP had no LPA phosphatase activity. In addition, the putative signal peptide-deleted LPAP showed no mitochondrial localization. The site of intracellular localization of endogenous LPAP was also mitochondria in MDCK cells and differentiated C2C12 cells. The LPAP homologous phosphatase, human prostatic acid phosphatase, also has LPA phosphatase activity. LPAP-stable transfected NIH 3T3 cells showed less phosphatidic acid, phosphatidylglycerol, and cardiolipin. These results suggested that LPAP regulates lipid metabolism in mitochondria via the hydrolysis of LPA to monoacylglycerol.

Amino Acid Sequence↗

Partial purification and characterization of a soluble acid phosphatase from the tapeworm, Hymenolepis diminuta.

An acid phosphatase activity (APA; EC 3.1.3.2) was demonstrated in homogenates of adult Hymenolepis diminuta. The APA was soluble based on the observation that it did not sediment at 130,000 g. APA was partially purified using a combination of differential centrifugation, ammonium sulphate precipitation, chloroform extraction, and gel and fast-protein-liquid-chromatography. This combination of techniques resulted in a preparation with a specific activity approximately 500 times greater than the crude enzyme preparation. The temperature and pH optima of the partially purified APA were 44 degrees C and pH 5.0. The enzyme appeared to be a monomer with a molecular weight of approximately 62,000. APA had a higher affinity for a greater activity towards aromatic than aliphatic phosphoesters, and phosphoryl transferase activity was demonstrable using 1-butanol and ethylene glycol as acceptors. APA was inhibited significantly by sodium dodecyl sulphate, fluoride, molybdate and tartrate, but CuSO4 and Fast Garnet GBC were poor inhibitors. The precise cellular localization and function of this enzyme remains unknown since it possesses characteristics of both cytoplasmic and lysosomal APA's of other organisms.

Acid Phosphatase↗

Characterization of human prostatic acid phosphatase radioiodinated by four different procedures.

Prostatic acid phosphatase was labeled by four different iodination procedures: chloramine-T, insoluble or soluble lactoperoxidase, and Bolton-Hunter. Enzyme labeled by the chloramine-T procedure had suboptimal precipitation characteristics in immunoassays, with 36 to 67% of the tracer precipitated in antibody excess. Analysis of the tracer on 7.5% sodium dodecyl sulfate polyacrylamide gel showed that as much as 30% of the radioactivity migrated away from the protein within 6 minutes after the electrophoretic run was begun. The nature of this fast migrating radioiodinated component was not determined. The failure to obtain a tracer labeled by the chloramine-T procedure with optimal immunoprecipitation characteristics led to investigation of alternate radioiodination procedures. Insoluble or soluble lactoperoxidase was less effective than chloramine-T in producing a tracer suitable for radioimmunoassay. In contrast, the Bolton-Hunter procedure produced a tracer that had optimal precipitation characteristics; 88 to 91% of the tracer was precipitated in antibody excess. The tracer was further purified by affinity chromatography to minimize the possibility of other protein contaminants compromising the specificity of a radioimmunoassay for the enzyme.

Acid Phosphatase↗

Monitoring of prostatic cancer by an enzyme-linked immunosorbent assay of serum prostatic acid phosphatase.

A longitudinal study of serum prostatic acid phosphatase (sPAP) in 167 cases of carcinoma of the prostate was made using an enzyme-linked immunosorbent assay. The sensitivity of the assay was valuable in accurately exploring the low levels of sPAP achieved after treatment by orchidectomy or oestrogens. For the majority of patients with metastatic disease, treatment resulted in the level of sPAP falling to normal within 3-9 months, but in about half of these patients the level of sPAP had begun to increase again, exponentially, within 2 years. This exponentially rising level of sPAP was well correlated with evidence of progression as indicated by bone scans. The rise of sPAP in M1 disease could not be accounted for by an attenuation of the suppression of testosterone. After hormone manipulation in M0 disease the sPAP generally fell to below 1.5 ng/ml and remained at this level for the duration of the study. In untreated M0 disease there were small fluctuations in the level of sPAP, and it had a higher baseline level. In both treated and untreated patients a rising level of sPAP above normal tended to indicate tumour progression.

Acid Phosphatase↗

Acid phosphatase activity in the mammalian nephron.

Lysosomal acid phosphatase (AcPase) activity was measured in individual segments of rat and rabbit nephrons employing 4-methylumbelliferyl phosphate as the substrate. Generation of reaction product was linear with incubation time up to 127 min and with tubule length. Activity was much higher in glomeruli and proximal tubules of rat than rabbit kidney. In both rat and rabbit there were higher activities in juxtamedullary than in superficial glomeruli. In rats, AcPase activity decreased from S1 to S3 segments, which parallels the known decrease in the number of lysosomes. Surprisingly, in rabbits of both sexes AcPase activity in the cortical collecting duct (CCD), which contains a limited number of lysosomes, was comparable to levels measured in the S1 and S2 segments of the proximal tubule. Similarly, in the male rat values for AcPase activity in the cortical thick ascending limb, distal convoluted tubule, CCD, and medullary collecting duct paralleled those in the S3 segment. These findings suggest that a considerable amount of AcPase in the distal nephron is either extralysosomal or that the amount of lysosomal AcPase activity per unit volume is greater in distal nephron segments compared with the proximal tubule. Different K'm values for AcPase in S1 segments and CCD were found in the rabbit, suggesting the presence of different isoenzymes.

Acid Phosphatase↗

Differential responses of rice acid phosphatase activities and isoforms to phosphorus deprivation.

Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.

Acid Phosphatase↗

Cytochemistry of tartrate-resistant acid phosphatase: 15 years' experience.

Tartrate-resistant acid phosphatase (T-AcP) has been used in the past 15 years as a specific test for the diagnosis of hairy cell leukemia (HCL). However, enzyme activity has been reported to be absent from the hairy cells of rare cases of HCL and to be present in the neoplastic cells of diseases other than HCL. In order to fully utilize T-AcP for the diagnosis of HCL, it is necessary to maximize the sensitivity and specificity of the staining method, to have adequate quality control to ensure technical and interpretative accuracy, and to prepare optimal cytologic and histologic materials for study. In blood, only the presence of cells with intense T-AcP activity is diagnostic of HCL (positive T-AcP test). In tissues other than blood, the presence of cells with intense enzyme activity may not be diagnostic for HCL; assessment of cell morphology and appreciation of the pattern of enzyme localization are also important. In studying the blood of over 1,000 patients, we have found a negative T-AcP test in two of 200 cases of HCL and a positive T-AcP test in three of 800 patients with diseases other than HCL. We believe that the T-AcP test, when performed and interpreted properly, is a useful diagnostic test for HCL.

Acid Phosphatase↗

Existence of tartrate-resistant acid phosphatase activity in differentiated lymphoid leukemic cells.

Acid phosphatase (AcP) in neoplastic cells from various lymphoid leukemias was examined. In the cytochemical studies, tartrate-resistant AcP (T-rAcP) activity was observed in the neoplastic cells from well-differentiated lymphoid leukemias such as adult T-cell leukemia (ATL), B-cell chronic lymphocytic leukemia (B-CLL), T-cell chronic lymphocytic leukemia (T-CLL), and hairy-cell leukemia (HCL). T-rAcP activity was also detected in a small number of leukemic cells obtained from T-cell acute lymphoblastic leukemia (T-ALL), while it was not detected in the neoplastic cells from null-ALL, macroglobulinemia, and multiple myeloma (MM). In the electrophoretical studies, fraction 1 (F-1), F-3, F-3b, and F-4 were completely tartrate-sensitive, while F-2 was partially resistant and F-5 was completely resistant. T-rAcP activity (F-5) was observed in ATL cells, B-CLL cells, and HCL cells, while it was not detected in ALL cells, macroglobulinemia cells, and MM cells. The present study indicates that T-rAcP activity is observed not only in HCL cells but also in the well-differentiated lymphoid cells such as ATL cells, B-CLL and T-CLL cells except the most highly differentiated forms of B-cells of MM and macroglobulinemia.

Acid Phosphatase↗

Variations in levels of acid phosphatase present in chicken whole leg meat.

Acid phosphatase (ACP) has been identified as a potential biomarker for endpoint temperature determination in further-processed poultry. Multiple analyses of the same sample for ACP have produced consistent results. The degree of variation in ACP levels present in different production lots has not been identified. This study was conducted utilizing a single flock of broilers. Birds were slaughtered on four separate days (replications), and whole leg, without skin, was homogenized. Proximate composition was analyzed for each replication. Water-soluble proteins were extracted from raw meat and assessed for initial ACP levels. Samples of meat were cooked to an internal temperature of 71.1 C. There were differences (P < 0.05) between replications for both moisture and fat content. When dry fat content was analyzed, no significant differences occurred between replicates. Initial ACP levels were different (P < 0.0001) between replicates (500.33 to 348.97 units of activity/kg). Levels of ACP activity after cooking were also different (P < 0.0001) between replicates (17.61 to 10.82 units of activity/kg). Percentage degradation of activity during cooking was similar (96.98 to 95.89%) between replicates. ACP levels were consistently measured within a replicate. Differences between replicates for both initial and cooked levels indicate a threshold level for determination of thermal endpoint would be difficult to establish. ACP may not be a sensitive measure to estimate the degree of doneness of meat samples in which initial ACP concentration is unknown. Identical raw sample required for such a comparison would be difficult for the processing industry to maintain.

Acid Phosphatase↗

Stereochemical course of phospho group transfer by human prostatic acid phosphatase.

The stereochemical course of the phospho transfer catalyzed by homogeneous human prostatic acid phosphatase was investigated using 31P nuclear magnetic resonance spectroscopy. Transphosphorylation from phenyl-(R)-[15O, 17O, 18O]phosphate to (S)-propane-1,2-diol occurs with overall retention of configuration at phosphorus. This stereochemical result is consistent with the interpretation that the hydrolysis of substrates by this enzyme proceeds by way of a covalent phosphoenzyme intermediate. Conditions for optimizing phospho transfer by this and related acid phosphatases have also been explored.

Acid Phosphatase↗

Evaluation of an enzyme-linked immunosorbent assay for prostatic acid phosphatase.

An enzyme-linked immunosorbent assay (ELISA) was developed to measure prostatic acid phosphatase in human sera. The value of this method was tested on four groups: patients with non-prostatic disease, with prostatic hypertrophy, and with untreated and treated prostatic carcinoma. The results of ELISA were also compared with those of enzyme immunoassay (EIA) and the conventional, enzymatic method. The specificity of ELISA as calculated from the hypertrophy group, was 76% against 68% for EIA and 71% for the conventional method. The sensitivity of ELISA, calculated from the untreated carcinoma group, was 57% against 60% for EIA and 70% for the conventional method. ELISA did not prove better than EIA or the conventional method in quantifying prostatic acid phosphatase in patients' sera.

Acid Phosphatase↗

Acid phosphatases of Sporothrix schenckii.

Sporothrix schenckii cells were grown on a medium containing yeast extract, neopeptone and glucose at 20 degrees C to obtain a mixture of mycelia and conidia, and at 35 degrees C to obtain yeast-like cells. The organism was maintained in the mycelial form, and its transformation to yeast at the higher temperature proceeded via conidia and 'intermediate cells' that then gave rise to yeast by a blastic mechanism. Cell-free extracts were analysed by PAGE at pH 8.0 and acid phosphatases (EC 3.1.3.2) were revealed by a sensitive detection reagent at pH 5.0. Mycelial, conidial and yeast extracts all had some acid phosphatase activity (M-I, C-I and Y-I) at the origin, although the proportion was highest for the yeast extracts. All of the bands that penetrated the gels had different electrophoretic mobilities. Mycelial and conidial extracts each had one other isoenzyme (M-II and C-II), while the yeast extracts had a total of five electrophoretically distinct acid phosphatases. Isoenzyme Y-II was further resolved into five closely related bands (Y-IIa to Y-IIe), the relative intensities of which varied with the phosphate nutrition of the yeast cells and the history of the extracts. The acid phosphatase isoenzymes were inhibited to various extents by sodium fluoride, L(+)-tartrate and phosphate, and showed interactions with citrate as opposed to acetate as the background buffer at pH 5.0.

Acid Phosphatase↗

Antagonistic effects of prolactin and oxytocin on tail fin regression and acid phosphatase activity in metamorphosing Ambystoma tigrinum.

We have found that the inhibition of thyroxine-induced tail fin regression by prolactin in larval tiger salamanders is antagonized by oxytocin. Other workers have shown that prolactin blocks the rise in activity of several hydrolytic enzymes that occurs in regressing tissue during metamorphosis. Here, we examine the effects of prolactin and oxytocin--given alone and in combination--on tail fin regression and acid phosphatase specific activity in this tissue. Both long-term (12-day) and short-term (48-hr) treatment paradigms using prolactin and oxytocin are investigated. The results show that long-term prolactin treatment of metamorphosing larvae blocks fin regression and the rise in acid phosphatase specific activity seen in metamorphosing controls; short-term prolactin treatment of metamorphosing larvae inhibits fin regression within 48 hr, but does not block the rise in acid phosphatase activity seen in controls; oxytocin antagonizes the effects of prolactin on tail fin regression; and oxytocin treatment (long-term or short-term) of metamorphosing larvae causes an elevation of acid phosphatase activity above that seen in metamorphosing controls. With long-term treatment, this effect of oxytocin is slightly antagonized by prolactin; with short-term treatment, no antagonism is observed even though an effect of prolactin on fin height is still evident. We have interpreted these results as suggesting that the effect of prolactin on hydrolase activity is not a prerequisite for its inhibitory effect on fin regression to occur.

Acid Phosphatase↗

Triglyceride metabolism in human liver: studies on hepatic phosphatidic-acid phosphatase in obese and non-obese subjects.

According to current concepts, soluble phosphatidic-acid phosphatase, converting phosphatidic acid into a diglyceride, is a rate-limiting enzyme in the hepatic biosynthesis of triglycerides. The present paper is the first report on this enzyme in human liver. The enzyme activity was assayed in ammonium sulphate precipitates of cytosol obtained from human liver biopsies. The activity was stimulated by preincubation with alkaline phosphatase and inhibited by Mg-ATP, suggesting that phosphorylation-dephosphorylation may be of some importance for the expression of the activity of the enzyme. When assayed under optimal conditions, the activity obtained in liver biopsies from normal-weight gallstone patients averaged 12.8 +/- 2.0 nmol min-1 (mg protein)-1 (mean +/- SEM) (n = 17). The enzyme activity was slightly higher in liver biopsies from morbidly obese subjects 16.4 +/- 2.8 nmol min-1 (mg protein)-1 (n = 14). The difference between the two groups of subjects was probably in part sex-dependent and was not statistically significant. A similar small and insignificant difference between the two groups of subjects was found when the enzyme activity was assayed in the maximally stimulated state--i.e. after incubation with alkaline phosphate. These findings suggest that an increased capacity of the soluble phosphatidic-acid phosphatase is not of major importance for the increased triglyceride synthesis known to occur in obesity. Other factors (i.e. availability of substrate and cofactors) may be of greater importance.

Adult↗