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PubMed1999

Cloning and comparative protein modeling of two purple acid phosphatase isozymes from sweet potatoes (Ipomoea batatas).

The sequence of cDNA fragments of two isozymes of the purple acid phosphatase from sweet potato (spPAP1 and spPAP2) has been determined by 5' and 3' rapid amplification of cDNA ends protocols using oligonucleotide primers based on amino acid information. The encoded amino acid sequences of these two isozymes show an equidistance of 72-77% not only to each other, but also to the primary structure of the purple acid phosphatase from red kidney bean (kbPAP). A three-dimensional model of the active site has been constructed for spPAP2 on the basis of the kbPAP crystallographic structure that helps to explain the reported differences in the visible and EPR spectra of spPAP2 and kbPAP.

Acid Phosphatase↗
PubMed1990

Purification and characterization of a tartrate-sensitive acid phosphatase of Trypanosoma brucei.

In search for invariant surface proteins in Trypanosoma brucei bloodstream forms, acid phosphatase was investigated. Earlier work had shown that part of the cellular phosphatase activity is associated with the flagellar pocket of the parasite. It is demonstrated that T. brucei contains at least two membrane-bound enzymes, one is sensitive to the inhibitor L-(+)-tartrate while the other is resistant. The tartrate-sensitive phosphatase was purified to homogeneity by monoclonal antibody affinity chromatography and shown to be a glycoprotein of low abundance (13,000 molecules/cell). It has an apparent molecular weight of 70,000 Da. The usefulness of acid phosphatase as a marker for characterizing the membrane lining the flagellar pocket is discussed.

Acid Phosphatase↗
PubMed1982

Comparison of enzyme-linked immunosorbent assay and radioimmunoassay for prostate-specific acid phosphatase in prostatic disease.

We compared results by an enzyme-linked immunosorbent assay (ELISA) with those by a standard radioimmunoassay (RIA) for detection and quantitation of prostate-specific acid phosphatase (EC 3.1.3.2) in serum. Control subjects, patients with benign prostatic hyperplasia, and patients in all four clinical stages of prostatic adenocarcinoma were tested. The upper limit of normal (95% of the population) by the ELISA was 2.0 micrograms/L, and by the RIA was 2.2 micrograms/L. In prostatic adenocarcinoma stage I (not detectable by digital rectal examination), ELISA was slightly more sensitive than RIA, but sensitivity was still relatively low (20%). As tumor mass increased (stages II through IV), the frequency of increased concentrations of prostatic acid phosphatase in serum also increased. We confirmed this increase in circulating enzyme in some cases of benign prostatic hyperplasia and suggest that this finding is related to either acinar cytolysis or an increase in acini size and number. Although prostate-specific acid phosphatase is not a cancer-specific enzyme, we conclude that its measurement may be of considerable value in monitoring prostatic disease.

Acid Phosphatase↗
PubMed1975

Acid phosphatase and adenosine triphosphatase activities in the cell wall of baker's yeast.

In order to establish whether a specific adenosine triphosphatase is present in yeast cell wall, hydrolysis rates for p-nitrophenylphosphate (acid phosphatase activity) and for ATP (ATPase activity) were compared under various conditions. Rate determinations were made with both, intact cells and with preparations containing secreted enzymes from protoplasts. Acid phosphatase and ATPase activities had the same pH profile and were susceptible in the same way to the repression by orthophosphate and to the inhibition by 2-deoxyglucose. The Lineweaver-Burk plot shows biphasic kinetic behaviour for the hydrolysis of either p-nitrophenylphosphate or ATP. This suggests the existence of two enzymes with different affinities for the substrates, or one enzyme with at least two active sites. The two activities differ in thermostability and only one activity could be completely abolished by heat treatment. The thermostable enzyme activity had K-m values of 0.475 mM for p-nitrophenylphosphate, and 0.040 mM for ATP. ATP behaved as a partially competitive inhibitor of p-nitrophenylphosphate hydrolysis. Substrate competition studies showed that only a non-specific acid phosphatase is responsible for the hydrolysis of ATP.

4-Nitrophenylphosphatase↗
PubMed1987

Hormonal regulation of acid phosphatase release by osteoclasts disaggregated from neonatal rat bone.

Osteoclasts disaggregated from neonatal rat long bones and incubated on plastic or glass substrates were found to release a considerable proportion of tartrate-resistant acid phosphatase into culture supernatants. Enzyme release was detectable in the supernatant medium of cultures containing as few as ten cells after 1 hr of incubation and proceeded in a linear manner for the ensuing 6 hr. Calcitonin (1 pg/ml) and cytochalasin B (5 micrograms/ml) inhibited release into the supernatant, suggesting that release represents enzyme secretion. Prostaglandin E1 induced transient inhibition followed by recovery; parathyroid hormone and 1,25(OH)2 vitamin D3 were without influence. Acid phosphatase release in these cultures shows a pattern of hormone responsiveness that coincides with the effects of these hormones on bone resorption by isolated osteoclasts. The extent of acid phosphatase release and its regulation by calciotropic hormones imply a central role for acid hydrolase secretion in osteoclastic bone resorption. The experimental system described in this study may facilitate analysis of the pharmacological hormonal and cellular regulation of osteoclastic function.

Acid Phosphatase↗
PubMed1977

Cytophotometric studies on the reaction kinetics of acid phosphatase in motoneurons marked by injection of Evans blue into the soleus muscle of the mouse.

Evans blue was injected into the soleus muscle of albino mice in order to mark retrogradely the corresponding motoneurons of the spinal cord. Subsequently, reaction kinetics of acid phosphatase were studied in the marked nerve cells. 41-51 motoneurons per animal were counted. They are located in the dorsolateral portion of the Rexed zone IX where they form motor cell columns approximately 1.5 mm in length. After identification of the motoneurons, the enzyme reaction for acid phosphatase was performed by covering the section with a gel film containing naphthol-AS-BI-phosphate-hexazonium-pararosanilin. The formation of the azo dye was measured cytophotometrically at 520 nm. During the first 10 min of registration, a linear decrease in transmission of 0.4 per cent/min was shown. Because of the unimodal distribution of changes in transmission, the motoneurons of the soleus muscle could not be characterized as fast or slow types on the basis of the reaction kinetics of acid phosphatase.

Acid Phosphatase↗
PubMed1986

The phagocytic function of Sertoli cells: a morphological, biochemical, and endocrinological study of lysosomes and acid phosphatase localization in the rat testis.

The lysosomal population of the seminiferous tubules of the rat was studied by conventional electron microscopy and electron microscopic histochemistry. Biochemical determinations of acid phosphatase were carried out in whole cell suspensions of seminiferous tubular cells or in different cell populations purified by sedimentation in albumin gradients. Lysosomes were rarely found in spermatogonia and primary spermatocytes. Young spermatids showed up to six lysosomes per section, and this number increased as spermatid maturation proceeded. Residual bodies had a very heterogeneous lysosomal content. Sertoli cells showed cyclical variations in their lysosomes. These were present in small numbers from stages I-IV of the cycle of the seminiferous epithelium and progressively increased to be numerous in Sertoli cells at stages VI-VIII. After spermiation, their rapidly decreased. Acid phosphatase contents were (nanomoles of nitrophenol formed per mg protein/min): whole cell suspension, 67.5 +/- 7.8; pachytene spermatocytes (72% purity), 76.5 +/- 10.6; round spermatids (73% purity), 95.0 +/- 2.8; residual bodies (88% purity), 96.0 +/- 14.2; and Sertoli cell-enriched fraction, 278.5 +/- 75.7. In a group of rats, endogenous LH and testosterone were lowered by administration of anti-LH antibodies. There was an intense degeneration of meiotic spermatocytes, which were phagocytized and digested by these immature testosterone-depleted Sertoli cells. It is concluded that lysosomes of the seminiferous epithelium show cyclical variations, with an increase toward the time of spermiation and a decrease after the residual bodies have been digested; the acid phosphatase and lysosomal contents of Sertoli cells are higher than those of germ cells, residual body disposal is probably initiated by autophagy and completed by Sertoli cell phagocytosis; and the phagocytic function of Sertoli cells is not hormone (testosterone) dependent.

Acid Phosphatase↗
PubMed1985

Erythrocyte acid phosphatase: species specificity in activity modulation by purine analogs.

The previous studies of the interaction of purine analogs and human erythrocyte acid phosphatase isozymes were extended to include erythrocyte acid phosphatase from seven other species. Consistent responses, similar to the observations with the several genotypically different human isozymes, were observed. The isozyme from chimpanzee erythrocytes was similar to the human B-type isozyme while the baboon and cow isozymes were at the other extreme in responsiveness and were more divergent from the B-isozyme than was the human A-type isozyme. The ACP from rabbit, dog, sheep and rhesus erythrocytes exhibited intermediate levels of responsiveness but did differ from the human A-type isozyme. Additional studies indicated some differences between the responsiveness of the partially purified erythrocyte enzyme and the low molecular weight ACP from liver.

Acid Phosphatase↗
PubMed1978

Relationship between extracellular enzymes and cell growth during the cell cycle of the fission yeast Schizosaccharomyces pombe: acid phosphatase.

By using the intact cells of the fission yeast Schizosaccharomyces pombe, the activity of acid phosphatase (EC 3.1.3.2) was compared through the cell cycle with the growth in cell length as a measure of cell growth. The cells of a growing asynchronous culture increased exponentially in number and in total enzyme activity, but remained constant in average length and in specific activity, In a synchronous culture prepared by selection or by induction, the specific activity was periodic in parallel with the increase in average cell length. When hydroxyurea was added to an asynchronous or a synchronous culture by selection, both specific and total activity followed the same continuous pattern as the growth in cell length after the stoppage of cell division. When oversized cells produced by a hydroxyurea pulse treatment to the culture previously syndronized by selection were transferred to a poor medium, they divided synchronously but could hardly grow in the total cell length. In this experimental situation, the total enzyme activity also scarcely increased through three division cycles. These results suggested that the increase in acid phosphatase in dependent on cell elongation.

Acid Phosphatase↗
PubMed1981

Small doses of 5 alpha-dihydrotestosterone mimic the effects of 5 alpha-androstane-3 beta, 17 beta-diol on acid phosphatase activity in the adult rat prostate gland.

These studies were designed to further investigate whether 5 alpha-androstane-3 beta, 17 beta-diol was exerting unique effects on rat prostate acid phosphatase activity or could possibly be exerting its actions by a small peripheral conversion to 5 alpha-dihydrotestosterone. Intraperitoneal administration of 5 alpha-dihydrotestosterone in doses of 1 mg, 100 microgram or 50 microgram per day starting 7 days after castration led to the restoration of normal characteristics of acid phosphatase activity. However, when 5 alpha-dihydrotestosterone was given in a dose of only 25 microgram per day starting 7 days after castration, the changes in acid phosphatase activity were indistinguishable from those found when 5 alpha-androstane-3 beta, 17 beta-diol was administered in a dose of 2 mg per day. This suggests that the effects of 5 alpha-androstane-3 beta, 17 beta-diol can be explained by its conversion to small amounts of 5 alpha-dihydrotestosterone.

Acid Phosphatase↗
PubMed1978

Distribution of acid phosphatase, beta-glucuronidase, and lysosomal hyaluronidase in the anterior segment of the rabbit eye.

Distribution of acid phosphatase, beta-glucuronidase, and lysosomal hyaluronidase in the anterior segment of the rabbit eye was studied biochemically. Acid phosphatase activity was higher in the anterior uvea and cornea but lower in the sclera. Beta-Glucuronidase activity was higher in the anterior uvea but lower in the corneoscleral tissues. Lysosomal hyaluronidase activity was higher in the anterior uvea. The inner layer of the corneoscleral junction showed the highest specific activity of beta-glucuronidase and lysosomal hyaluronidase among the corneoscleral tissues. Lysosomal hyaluronidase activity was detected in all corneoscleral tissues.

Absorption↗
PubMed1987

Tartrate-resistant acid phosphatase in bone and cartilage following decalcification and cold-embedding in plastic.

Tartrate-resistant acid phosphatase (TRAP) has been proposed as a cytochemical marker for osteoclasts. We have developed an improved technique for the localization of TRAP in rat and mouse bone and cartilage. This procedure employs JB-4 plastic as the embedding medium, permits decalcification, and results in improved morphology compared with frozen sections. Peritoneal lavage cells were used to determine the appropriate isomer and concentration of tartrate necessary for inhibition of tartrate-sensitive acid phosphatase. After incubation in medium containing 50 mM L(+)-tartaric acid, osteoclasts and chondroclasts were heavily stained with reaction product. On the basis of their relative sensitivity to tartrate inhibition, three populations of mononuclear cells could also be distinguished. These three populations may represent: heavily stained osteoclast/chondroclast precursors; sparsely stained osteoblast-like cells lining the bone surface; and unstained cells of monocyte-macrophage lineage. Our results are consistent with the use of TRAP as a histochemical marker for study of the osteoclast.

Acid Phosphatase↗
PubMed1975

Semiquantitative cytochemical determination of acid phosphatase, beta-glucuronidase, and beta-glucosaminidase activity in peripheral blood lymphocytes.

Activity of acid phosphatase, beta-glucuronidase, and beta-glucosaminidase in peripheral blood lymphocytes was determined cytochemically in 20 normal subjects, 10 male and 10 female, by the use of BARKA and ANDERSON's (1962), HAYASHI et al. (1964) and HAYASHI's (1965) methods, respectively. Results obtained were semiquantitatively according to subdivision of lymphocytes into enzyme-negative and enzyme-positive cells. Enzyme-positive lymphocytes were divided into cells with granular, mixed granular and diffuse enzymatic reaction type. In the first two types of cytochemical reaction a number of enzyme-positive lysosomal granules were counted and expressed in terms of both absolute count and percentage of circulating lymphocytes. Enzyme-positive lymphocytes represented 80.3%, 40.5% and 41.5% of the total lymphocyte count in regard to the presence of acid phosphatase, beta-glucuronidase, and beta-glucosaminidase, respectively.

Acid Phosphatase↗
PubMed1981

Acid phosphatase from needles of Pinus silvestris L. Purification of two interconvertible enzyme forms and characterization of a low-molecular weight factor associated with the enzyme.

Two main forms of acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) have been isolated from needles of Pinus silvestris L. The isoelectric points determined by isoelectro-focusing are 3.6 and 9.4. The molecular weights of both forms were estimated as 68 000. The two forms have similar kinetic properties. Chromatography of the acidic enzyme form on DEAE-cellulose results in conversion to the basic form. Interconversion in the reverse direction was demonstrated to occur on incubation of the basic enzyme form with a pine-needle homogenate or with a low-molecular weight fraction thereof. These findings suggest that the interconvertibility between the main enzyme forms is a result of an association of the basic form with a low-molecular weight factor carrying multiple negative changes. This factor has been purified and tentatively identified as an oligoribonucleotide or a fragment of RNA. The implications of these findings for the application of acid phosphatase isoenzymes as genetic markers in forest trees are discussed.

Acid Phosphatase↗
PubMed1984

Structural analysis of the two tandemly repeated acid phosphatase genes in yeast.

We have sequenced the genetically linked genes for repressible (PHO5) and and constitutive (PHO3) acid phosphatase from S. cerevisiae. Both genes are located on a 3.91 Kb BamHI and HpaI fragment, in the order (5') PHO5, PHO3 (3'). The mRNA transcripts have been analysed by S1-nuclease mapping. They show heterogenous initiation sites. Each of the PHO5 and PHO3 genes codes for 467 amino acids as deduced from the DNA sequence. The coding regions of the two genes show homology both at the nucleotide (82%) and the amino acid (87%) level. In the coding sequences, long stretches of homologous regions are flanked by small non-homologous regions. The nucleotide homology (65%) extends to some length into the 5' and 3' non-coding flanking sequences. Further upstream sequences are unrelated. The comparison of the NH2-terminal amino acid sequence deduced from the nucleotide sequence, with that of purified repressible acid phosphatase revealed the presence of a putative signal peptide.

Acid Phosphatase↗
PubMed1990

Sequence homology between purple acid phosphatases and phosphoprotein phosphatases. Are phosphoprotein phosphatases metalloproteins containing oxide-bridged dinuclear metal centers?

The amino acid sequences of mammalian purple acid phosphatases and phosphoprotein phosphatases are shown to possess regions of significant homology. The conserved residues contain a high percentage of possible metal-binding residues. The phosphoprotein phosphatases 1, 2A and 2B are proposed to be iron-zinc metalloenzymes with active sites isostructural (or nearly so) with those of the purple phosphatases.

Acid Phosphatase↗
PubMed1984

The stability of prostatic acid phosphatase, as measured by a capture immunoenzyme assay.

A capture immunoenzyme assay (CIEA) for prostatic acid phosphatase (PAP) was developed and used to study the stability of this isoenzyme. Immunospecifically purified goat antibodies to PAP were covalently bound to special discs and used to capture the enzyme in serum samples in a weakly acidic medium during the first incubation (2 h) at 37 degrees C. The capture enzyme was then measured by its catalytic activity with p-nitrophenyl phosphate as substrate during the second incubation (1 h) at 37 degrees C. As much as 98% of the PAP in test specimens was captured and measured by this CIEA. The test results were expressed as enzymatic activity (U/l), extrapolated from a standard curve which was linear between 0.026 and 70 U/l. In test sera stored at 4 degrees C, the PAP was variably stable for 7 to 70 days, but the enzyme was quite stable in serum when stored at -20 degrees C for at least 156 days. At room temperature, when the sera were appropriately acidified, there was no loss of enzymatic activity for periods of 15 days, and in some cases, a large proportion of activity was still intact after 70 days. At 4 degrees C, as well as -20 degrees C, acidified serum and the partially purified PAP standard showed complete stability for at least 7 months. The CIEA reactivity of positive test specimens was inhibited by L(+)-tartaric acid, but not by cupric sulfate. The acid phosphatases of blood cell extracts were non-reactive in the CIEA procedure. The CIEA results of 224 serum samples from patients with and without prostate cancer correlated very well with those obtained by two direct enzymatic and two commercial RIA procedures, with correlation coefficients between 0.960 and 0.993, and diagnostic agreement between 86% and 100%.

Acid Phosphatase↗