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Transcriptional regulation of the tartrate-resistant acid phosphatase (TRAP) gene by iron.

Tartrate-resistant acid phosphatase (TRAP) was first identified in cells from patients with hairy cell leukaemia. Subsequently, it has been found in other leukaemias, B-lymphoblastoid cell lines, osteoclasts and subsets of normal lymphocytes, macrophages, and granulocytes. Recent data indicate that TRAP and porcine uteroferrin, a placental iron-transport protein, represent a single gene product. However, the intracellular role of TRAP is unknown. We used a full-length human placental TRAP cDNA probe to examine TRAP expression in human peripheral mononuclear cells (PMCs). TRAP mRNA increased 50-75-fold after 24 h in unstimulated PMC cultures. Cell-fractionation experiments indicated that monocytes were the main cell population accounting for increased TRAP mRNA transcripts, and this was confirmed by histochemical staining for TRAP enzyme activity. Because expression of other iron-binding and -transport proteins is controlled by iron availability, we examined the role of iron in regulating TRAP expression. Increase of TRAP mRNA transcripts in PMCs was inhibited by 50 microM desferrioxamine, a potent iron chelator. The 5' flanking region of the TRAP gene was cloned from a mouse genomic library. In preliminary transient transfection experiments, it was determined that the 5'-flanking region of the TRAP gene contained iron-responsive elements. Therefore, a series of stably transfected HRE H9 cell lines was developed bearing genetic constructs containing various segments of the murine TRAP 5' promoter region driving a luciferase reporter gene. Treatment of transfectants with 100 micrograms/ml iron-saturated human transferrin (FeTF) was performed to assess iron responsiveness of the constructs. Constructs containing a full-length TRAP promoter (comprising base pairs -1846 to +2) responded to FeTF with a 4-5-fold increase of luciferase activity whereas constructs containing only base pairs -363 to +2 of the TRAP promoter did not respond. Constructs containing 1240 or 881 bp of the TRAP promoter gave only a 1.5- to 2-fold increase of luciferase activity with FeTF. In all cases, increase of luciferase activity was blocked by desferrioxamine. Cells transfected with another luciferase construct driven by a simian virus 40 promoter did not show any increase of luciferase activity with FeTF. These data indicate that expression of TRAP is regulated by iron and that this regulation is exerted at the level of gene transcription. The transfection experiments also suggest that the region of the TRAP 5'-flanking sequence between base pairs -1846 and -1240 contains an iron regulatory element.

Acid Phosphatase↗

Tumor antigen and acid phosphatase isoenzyme in prostatic cancer.

Plasma and prostatic fluid from man, dog, and baboon were measured for carcinoembryonic antigen (CEA) by a radioimmunoassay technique. No CEA was detected in plasma, prostatic fluid, or seminal fluid in 12 dogs and three baboons. Elevated CEA (less than 2.5 ng/ml) was found in 13 of 20 human prostatic fluids. It was inferred that there was no immunologic cross-reactivity of CEA among man, dog, and baboon. CEA has been isolated and purified from liver tumors. Biochemical studies reveal that CEA consists of 60 percent carbohydrate and 40 percent protein. It contains the following carbohydrates: fucose, mannose, galactose, sialic acid, N-acetylglucosamine, and a small amount of N-acetylgalactosamine. The following amino acids were found in CEA: lysine, histidine, arginine, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, emthionine, isoleucine, leucine, tyrosine, phenylalanine, and cysteine. The amino acid sequence (first 30 amino acids) of the N-terminal has been determined. The N-terminal amino acid was lysine. Using this study as a model, other tumor antigens from prostatic tumor tissues are being investigated. The acid phosphatase isoenzyme from prostatic tissue was also studied. After a series of purifications, two chromatographic fractions were obtained. Treatment with neuraminidase removed the sialic acid content of the molecule, changed the isoelectric focusing patterns, and abolished the chromatographic heterogeneity. Sedimentation studies indicated a molecular weight of about 100,000. Biochemical studies showed that prostatic acid phosphatase isoenzyme is a glycoprotein which consists of 7 percent carbohydrate and 93 percent protein. It contains fucose, galactose, mannose, sialic acid, N-acetylglucosamine, and the following amino acids: aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, tryptophan, and cysteine. An antiserum to this purified prostatic acid phosphatase isoenzyme is being prepared in animals.

Acid Phosphatase↗

Generation of monoclonal antibodies to prostatic acid phosphatase isoenzyme 2 and application in solid-phase enzyme immunoassay.

Monoclonal antibodies specific to prostatic acid phosphatase (PAP) isoenzyme 2 were generated by using an improved hybridoma technique. After three subcutaneous immunizations and three intravenous boosters, cell fusion experiments were performed. The hybrid cells were first cultured in a semisolid medium containing methylcellulose and later transferred to a liquid medium for further subculture. Out of a total of 600 colonies recovered after two cell fusion experiments, 13 were shown to exhibit affinity to PAP isoenzyme 2 by radioimmunoassay. Nine hybrid cell lines which showed high affinity and specificity were established for further evaluation. Their immunoglobulin subclass was determined to be immunoglobulin G. The association constants between PAP isoenzyme 2 and each monoclonal antibody were determined by titration curve in radioimmunoassay (RIA). Three of them (PAP 1, PAP 03, and PAP 019) were shown to be over 1 X 10(9) M-1. From the results of a matrix cross-matching procedure, a pair of antibodies (PAP 03 and PAP 1) reacting with discrete antigenic determinants were identified for preparing a solid phase sandwich enzyme immunoassay (EIA) kit. The designed EIA procedure could be performed within 40 min in a one-stage incubation protocol. The assay time was shorter than that of other commercial RIA or EIA kits, and the sensitivity was 0.4 ng/ml which was comparable to that of RIA kits. The EIA kit was shown not to cross-react with human thyroid stimulating hormone, alpha-fetoprotein, carcinoembryonic antigen, and acid phosphatases derived from tissues other than prostate. Therefore, this design was a simple and rapid method with high sensitivity and specificity for determining PAP isoenzyme 2 in human serum.

Acid Phosphatase↗

Production and properties of phytase and acid phosphatase from a sake koji mold, Aspergillus oryzae.

We identified three types of acid phosphatase (ACP-I, ACP-II, and ACP-III) produced by Aspergillus oryzae in a submerged culture using only phytic acid as the phosphorous substrate. The optimum pH for the activities of the three enzymes was in the range of 4.5 to 5.5. Analysis of the substrate specificities of these enzymes revealed that ACP-I and ACP-III were acid phosphatases, and ACP-II was a phytase. These enzymes were produced during different periods of mycelial growth: ACP-II was produced during the early phase of cultivation (around 24 h), and ACP-I was produced between 24 to 72 h. ACP-III was detected after the production of ACP-I and ACP-II had ceased. The release of phosphate from phytic acid was expected to be due to the cooperative hydrolysis of these enzymes.

Journal Article↗

Eccentric localization of osteocytes expressing enzymatic activities, protein, and mRNA signals for type 5 tartrate-resistant acid phosphatase (TRAP).

Enzymatic activity of type 5 tartrate-resistant acid phosphatase (TRAP) has been regarded as one of the reliable markers for osteoclasts and their precursors. The presence of TRAP activity in osteocytes near the bone resorbing surface has also been pointed out in some reports. However, the significance of TRAP reactions in osteocytes remains controversial and, in fact, there is no agreement as to whether the histochemical enzyme reactions in osteocytes represent the TRAP enzyme generated by the respective osteocytes or is a mere diffusion artifact of the reaction products derived from the nearby osteoclasts. Current histochemical, immunohistochemical, and in situ hybridization studies of rat and canine bones confirmed TRAP enzyme activity, TRAP immunoreactivity, and the expression of Trap mRNA signals in osteocytes located close to the bone-resorbing surface. TRAP/Trap- positive osteocytes thus identified were confined to the areas no further than 200 microm from the bone-resorbing surface and showed apparent upregulation of TRAP/Trap expression toward the active osteoclasts. Spatial and temporal patterns of TRAP/Trap expression in the osteocytes should serve as a valuable parameter for further analyses of biological interactions between the osteocytes and the osteoclasts associated with bone remodeling.

Acid Phosphatase↗

Human lysosomal acid phosphatase is transported as a transmembrane protein to lysosomes in transfected baby hamster kidney cells.

BHK cells transfected with human lysosomal acid phosphatase (LAP) cDNA (CT29) expressed 70-fold higher enzyme activities of acid phosphatase than non-transfected BHK cells. The CT29-LAP was synthesized in BHK cells as a heterogeneously glycosylated precursor that was tightly membrane associated. Transfer to the trans-Golgi was associated with a small increase in size (approximately 7 kd) and partial processing of the oligosaccharides to complex type structures. CT29-LAP was transferred into lysosomes as shown by subcellular fractionation, immunofluorescence and immunoelectron microscopy. Lack of mannose-6-phosphate residues suggested that transport does not involve mannose-6-phosphate receptors. Part of the membrane-associated CT29-LAP was processed to a soluble form. The mechanism that converts CT29-LAP into a soluble form was sensitive to NH4Cl, and reduced the size of the polypeptide by 7 kd. In vitro translation of CT29-derived cRNA in the presence of microsomal membranes yielded a CT29-LAP precursor that is protected from proteinase K except for a small peptide of approximately 2 kd. In combination with the sequence data available for LAP, these observations suggest that CT29-LAP is synthesized and transported to lysosomes as a transmembrane protein. In the lysosomes, CT29-LAP is released from the membrane by proteolytic cleavage, which removes a C-terminal peptide including the transmembrane domain and the cytosolic tail of 18 amino acids.

Acid Phosphatase↗

Identical populations of phagocytes and dying neurons revealed by intravascularly injected horseradish peroxidase, and by endogenous glutaraldehyde-resistant acid phosphatase, in the brains of chick embryos.

Intravascularly injected horseradish peroxidase selectively labels certain classes of cells in the brains of chick embryos: phagocytes, which have characteristic distributions and resemble either gitter cells or microglia; and some, but not all, dying neurons. Healthy neurons are not labelled. If the isthmo-optic nucleus is caused to degenerate by an intraocular injection of colchicine on the opposite side, most of its neurons take up peroxidase. However, destroying the afferents to the isthmo-optic nucleus increases its loss of neurons without affecting the number labelled. In sections double-reacted for horseradish peroxidase and endogenous acid phosphatase, all, and indeed only, the peroxidase-labelled cells exhibit intense, clumped acid phosphatase activity which resists glutaraldehyde fixation. This is true of all cell types in both normal and operated embryos. Even healthy neurons exhibit acid phosphatase activity, but this can be distinguished, because it is largely inhibited by fixation with glutaraldehyde.

Acid Phosphatase↗

Biochemical and genetic analysis of pre-stalk specific acid phosphatase in Dictyostelium.

The only known enzymatic marker of pre-stalk cells at the slug stage of development in Dictyostelium discoideum is an isozyme of acid phosphatase, AP2. There is another isozyme of acid phosphatase, AP1, which is present in vegetative cells and is not cell-type specific. We have purified these isozymes and find they differ in Km and thermostability. Both isozymes are affected by mutations in a single locus, acpA. Two mutations in the acpA locus abolished all activity of both AP1 and AP2 while a third mutation reduced the activity and altered the thermostability of both isozymes. It is likely that acpA is the structural gene responsible for both AP1 and AP2. The cell-type specificity of AP2 appears to result from differences in the modification of the acpA gene product between pre-spore and pre-stalk cells. The resulting difference in AP2 provides a useful marker for pre-stalk cells.

Acid Phosphatase↗

Development of a kinetic assay for band 5b tartrate-resistant acid phosphatase activity in serum.

BACKGROUND: Band 5 tartrate-resistant acid phosphatase (TrACP; EC 3. 1.3.2) consists of two isoenzymes, bands 5a and 5b, of which band 5b TrACP is considered to be derived from bone. However, no kinetic method for the specific measurement of band 5b TrACP in serum is available. Our aim was to develop a kinetic assay method for the specific measurement of band 5b TrACP in serum. METHODS: Band 5b TrACP was measured kinetically in serum as tartrate-resistant fluoride-sensitive heparin-resistant ACP with 2, 6-dichloro-4-acetylphenyl phosphate as substrate at pH 6.6. RESULTS: Heparin inhibited band 5a TrACP but had no effect on band 5b TrACP in serum or in bone extract. The presence of EDTA or ascorbic acid had no effect, but dithiothreitol inhibited enzyme activity. The within-run (n = 20) and between-run (n = 20) CVs of band 5b TrACP activity were 3.3-5.8% and 5.0-7.3%, respectively. The mean +/- SD values of band 5b TrACP activity in males (n = 25) and females (n = 57) 20-29 years of age by this method were 8.0 +/- 2.2 U/L and 6.4 +/- 1.8 U/L, respectively. The band 5b TrACP value was significantly higher in females >50 years of age compared with the younger subjects (20-29 years). The highest band 5b TrACP values were among children younger than 15 years. CONCLUSIONS: This kinetic assay is a simple and specific method for the measurement of band 5b TrACP in serum samples and is useful in the evaluation of bone turnover activity.

Acid Phosphatase↗

Relationships between cell surface protease and acid phosphatase activities of Leishmania promastigote.

A correlation between the ratio of the cell surface protease activity to phosphatase activity and the complexity of the pattern of cell surface exposed polypeptides of Leishmania promastigotes was demonstrated for various strains grown under similar conditions. The ratio of the cell surface protease activity to acid phosphatase activity was high for L. major and L.b. panamensis and it correlates with the expression of a single polypeptide of 63 KDa on their cell surface. Intermediate and lower ratios of these enzymatic activities relate with more complex radio-iodinated patterns: two main bands in L.b. guyanensis (70 and 58 KDa) and L.b. braziliensis (72 and 60 KDa) and three main bands 65, 50, 27 KDa in all L.m. mexicana strains tested. Evidence is presented that the acid phosphatase located on the L.m. mexicana cell surface is not an artifact due to a secondary absorption of the secreted acid phosphatase from the culture medium. These results confirm the Leishmania antigen cell surface heterogeneity. The implications on the biology of Leishmania and the clinical manifestation of leishmaniasis are discussed.

Acid Phosphatase↗

A novel immunoassay for the determination of tartrate-resistant acid phosphatase 5b from rat serum.

Osteoclasts secrete tartrate-resistant acid phosphatase 5b (TRACP 5b) into the circulation. We have developed an immunoassay for the determination of rat TRACP 5b activity. Intra-assay variation of the immunoassay was 4.5%, interassay variation was 3.8%, dilution linearity was 104.6 +/- 7.6%, and recovery of recombinant rat TRACP was 99.1 +/- 5.8%. We studied serum TRACP 5b as a marker of bone resorption using orchidectomized (ORC) rats as a model for osteoporosis and age-matched sham-operated rats as controls in a 6-month study. After the operation, trabecular bone mineral density decreased significantly more in the ORC group than in the sham group, whereas cortical bone mineral density increased similarly in both groups. Serum TRACP 5b activity was significantly elevated within the first week after ORC, returned to the control level in the third week, and was not increased above the sham level at any of the later time points. At 6 months, trabecular bone volume was 80% lower in ORC rats than in controls. Osteoclast number per trabecular bone perimeter was slightly increased, but the absolute number of osteoclasts in trabecular bone was significantly decreased. These results suggest that absolute bone resorption is increased within the first week after ORC. Later, it is decreased because there is less bone to be resorbed. However, relative bone resorption (compared with the amount of remaining bone) is still increased, leading to further bone loss. We conclude that serum TRACP 5b is a useful marker for monitoring changes in the bone resorption rate in rat ORC model.

Acid Phosphatase↗

[Critical study of extra-lysosomal acid phosphatase localizations in thyroid follicular cells by the Gomori reaction (author's transl)].

With the Gömöri technique, lead precipitates have been found in thyroid follicle cells in unusual localizations such as apical hyaloplasm and microvilli; it has been established that they were actually significant for acid phosphatase activity: constant results in spite of repeated controls and several variations from the original cytochemical technique, allow to think that lead precipitates were not merely artefactual, but actually significant of enzymatic activity. However it is pointed to the fact that the origin of the enzyme has to be questioned; it is assumed that most likely acid phosphatase has diffused from its original lysosomal site. Such diffusion implies variations of the selective permeability of lysosomal membranes; inappropriate relation between the quantity of enzyme present in these organelles and the quantity of substrate used might also be considered, though changes in the amount (resp. concentration) of substrate remained ineffective and induced no modification in the localization of observed enzymatic activity. In addition, one point of interest is an obvious relation between the observed enzyme diffusion and the state of activity resp. rest of the cell; in the present state of investigations, this remains unexplained and likely related to factors escaping control during processing; moreover, no explanation can be provided for the fact that it revealed impossible to avoid such diffusion even by means of variations of the numerous parameters involved in the Gömöri technique. So that it finally appears necessary to remain on a critical position regarding the results at the ultrastructural level of this standardized technique, and there is no doubt it would reveal useful that several assumptions in the literature about extra lysosomal acid phosphatase activity should be reinvestigated with a similar critical purpose.

Acid Phosphatase↗

Acid phosphatase activity in Nocardia brasiliensis and Nocardia asteroides.

Nocardia asteroides and N. brasiliensis strains were found to possess acid phosphatase activity. This enzyme was found to be cell-associated and its activity paralleled the cell mass increase seen during the Nocardia growth cycle. Of the strains tested, N. brasiliensis exhibited the highest enzymatic activity. Implications of these findings are related to current evidence which indicates that other microbial acid phosphatases may constitute potential pathogenic factors for humans.

Acid Phosphatase↗

Selective localization of a Golgi apparatus acid phosphatase isoenzyme in bone using pyridoxal-5'-phosphate.

Substrates commonly used for localizing bone Golgi apparatus (GA) acid phosphatase (AcPase), e.g., beta-glycerophosphate, p-nitrophenylphosphate, cytidine-5'-monophosphate, and di(dicyclohexylammonium)-2-napthylthiolphosphate, give strong staining not only of GA but also of lysosomes. Thiamine pyrophosphate and inosine-5'-monophosphate--substrates that give good GA staining in some soft tissues--give only lysosomal staining in bone. No previously used substrate or substrate-effector combination has selectively localized the GA acid phosphatase in bone. This article describes results using a new AcPase medium having pyridoxal-5'-phosphate (PLP) as substrate. In bone this medium produced strong staining of the osteoblast GA, but relatively little staining of lysosomes, including lysosomes in osteoclasts. The weak lysosomal staining was almost totally eliminated, without affecting the GA reaction, by pretreating the tissue in 0.3% NH3 solution. Conversely, elevated ionic strength of the substrate medium eliminated the GA reaction, while having little effect on lysosomal staining. The GA enzyme was very sensitive to 1 mM tartrate whereas the lysosomal enzyme was not. These differences suggest the presence of distinct isoenzymes in the two locations. The distribution of osteoblasts with stained GA coincided with the distribution of strongest alkaline phosphatase activity and rapid bone mineralization, supporting previous suggestions that osteoblast GA AcPase is involved in the processing of one or more newly synthesized bone matrix components.

Acid Phosphatase↗

Apparent heterogeneity of hepatic lysosomes due to membrane-bound acid phosphatase.

Hepatic lysosomes have been fractionated by rate sedimentation and by isopycnic banding. In all experiments, the distribution of acid phosphatase differed from that of the other lysosomal enzymes. Evidence is presented that this difference is due not to the separation of lysosomes from different cell types, but simply reflects the membrane location of a part of the acid phosphatase.

Acid Phosphatase↗

Relationship between the acid phosphatases of the Kurloff body and the major 30-35 kDa glycoproteins of the Kurloff cell.

This study deals with the acid phosphatase (AcPase) of the Kurloff body (KB), a large (10 microns diameter) periodic acid-Schiff-positive lysosomal inclusion body present in Kurloff cells (KC). KC AcPase were extracted, with similar yields, either with non-ionic detergent solution or after Dounce homogenization in low ionic strength buffer suggesting that they mainly correspond to hydrosoluble AcPase. After DEAE-cellulose chromatography of such crude Dounce-extracts, 97% of KC AcPase activity was recovered in the unbound glycoprotein fraction (peak I)1). The main protein content consisted of, as testified by SDS-PAGE analysis, major KC glycoproteins of 30-35 kDa. Thus, KC AcPase, and particularly sialoAcPase, may be assumed to correspond to these N-glycosylproteins among which the presence of alpha (2,6) sialoglycoproteins was previously established. Following electrophoresis on a 4-15% gradient native polyacrylamide gel or isoelectric focusing, the two size populations (200 kDa and 500 kDa) and up to 20 isoforms of KC AcPase were respectively detected by zymography in peak I. After Clostridium-derived sialidase digestion of peak I, the highly active bands observed at pH 3.5-5.2 disappeared. These zymographic patterns were similar to those obtained with crude extracts. After Concanavalin A (ConA)-Sepharose chromatography of peak I, the single ConA-bound glucosamine-labelled peak, eluted at 200 methyl-alpha-D-mannopyranose, contained the AcPase activity while the ConA-unbound peak was devoid of any acid phosphatase activity. After SDS-PAGE analysis, the ConA-bound fraction appeared to correspond only to a single broad protein band in the 30-35 kDa zone.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗

Widespread expression of tartrate-resistant acid phosphatase (Acp 5) in the mouse embryo.

Tartrate-resistant acid phosphatase (TRAP, Acp 5) is considered to be a marker of the osteoclast and studies using 'knockout' mice have demonstrated that TRAP is critical for normal development of the skeleton. To investigate the distribution of TRAP in the mammalian embryo, cryostat sections of 18 d murine fetuses were examined by in situ hybridisation, immunohistochemistry and histochemical reactions in situ. Abundant expression of TRAP mRNA was observed in the skin and epithelial surfaces of the tongue, oropharynx and gastrointestinal tract including the colon, as well as the thymus, ossifying skeleton and dental papillae. TRAP protein was identified at the same sites, but the level of expression in the different tissues did not always correlate with apparent enzyme activity. The findings indicate that abundant TRAP expression is not confined to osteoclasts in bone, but occurs in diverse tissues harbouring cells of bone marrow origin, including dendritic cells and other cells belonging to the osteoclast/macrophage lineage.

Acid Phosphatase↗