Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alkaline phosphatase from KB cells was purified, characterized, and compared to placental alkaline phosphatase, which it resembles immunologically. Two nonidentical nonomeric subunits of the KB phosphatase were found. The two subunits, which have apparent molecular weights of 64,000 and 72,000, can be separated on polyacrylamide gels containing sodium dodecyl sulfate. The Mr = 64,000 KB subunit appears to be identical in protein structure to the monomer of placental alkaline phosphatase. The Mr = 72,000 KB subunit, while differing in the NH2-terminal amino acid, appears also to be very similar to the placental alkaline phosphatase monomer. Both KB phosphatase subunits bind (32P)phosphate, and bind to Sepharose-bound anti-placental alkaline phosphatase. Native KB phosphatase is identical to the placental isozyme in isoelectric point, pH optimum, and inhibition by amino acids, and has a very similar peptide map. The data presented support the hypothesis that the Mr = 64,000 KB phosphatase subunit may the the same gene product as the monomer of placental alkaline phosphatase. This paper strengthens the evidence that the gene for this fetal protein, normally repressed in all cells but placenta, is derepressed in the KB cell line. In addition, this paper presents the first structural evidence that there are two different subunit proteins comprising the placental-like alkaline phosphatase from a human tumor cell line.
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PMID:Characterization of KB cell alkaline phosphatase. Evidence of similarity to placental alkaline phosphatase. 126 37

We have developed hybridization probes that clearly distinguish the RNA transcripts of the two closely related human heat-stable alkaline phosphatase genes. RNA from the PLAP-1 gene, encoding the term placental alkaline phosphatase, is the predominant transcript in placenta from 8 weeks to term. Transcripts from the PLAP-2 gene, encoding the germ-cell or PLAP-like enzyme, are also detectable in the placenta, but at no more than 2 per cent the level of PLAP-1 transcripts.
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PMID:Trace expression of the germ-cell alkaline phosphatase gene in human placenta. 172 15

Using alkaline phosphatase isozyme-specific immunocatalytical assays, the content of isozymes was determined in normal mucosas and adenocarcinomas from human colon or rectum. Tumor levels of both the tissue (liver)-unspecific and the placental-like alkaline phosphatase (PLAP-like) were elevated compared to normal mucosas of the same patients. Such elevations have been reported previously, particularly in seminomas and ovarian tumors. In several tumors, moreover, the intestinal isozyme was expressed in lesser amounts than in the adjacent mucosa. The present results indicate that the activation of two of the phosphatase isozymes, including expression of the typical germ cell line phosphatase (the PLAP-like isozyme), may occur even in nongonadal tumors. This may reflect an induction pattern of phosphatase isozymes, with implications for malignant transformation also in other tumors.
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PMID:Identification and characterization of alkaline phosphatase isozymes in human colorectal adenocarcinomas. 187 13

The significance of the PLAP (Placental alkaline phosphatase)/PLAP-like isozyme as tumour marker in relation to CA 125 and TPA for the monitoring of patients with malignant ovarian epithelial tumours was evaluated. Of all patients (n = 85), 40% had all three markers elevated. CA 125 being the most sensitive (60%), and the PLAP/PLAP-like isozyme and TPA both 40%. A tendency to certain tumour marker patterns of these three antigens in serum can be seen with regard to histopathology. Serous and anaplastic adenocarcinomas usually have all three markers moderately elevated, mucinous and mesonephric adenocarcinomas both have low incidences and low average levels of all three markers. Endometrioid and non-mucinous adenocarcinomas are often associated with high levels of the PLAP/PLAP-like isozyme and CA 125, while TPA shows moderate elevation. The PLAP/PLAP-like isozyme is positively correlated to tumour burden and the outcome of the disease. It may provide additional information on CA 125 in the monitoring of patients with ovarian cancer.
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PMID:Placental alkaline phosphatase (PLAP)/PLAP-like alkaline phosphatase as tumour marker in relation to CA 125 and TPA for ovarian epithelial tumours. 209 51

The alkaline phosphatase (AP) synthesized by human tumor cells closely resembles human placental AP (PLAP). Little is known about the molecular events that lead to the expression of a placenta-like AP in tumor cells. The complementary DNA encoding the AP expressed by a choriocarcinoma cell line, BeWo, was isolated and characterized. The complementary DNA is the product of the germ cell AP (Nagao isozyme) gene and not of the term PLAP gene. Like placental AP, the tumor AP can be released from the cell membrane by a phosphaditylinositol-specific phospholipase C and has a phosphaditylinositol-glycan (PI-glycan) moiety at the COOH terminus. Immunoprecipitation of phosphaditylinositol-specific phospholipase C-treated AP and analysis by polyacrylamide gel electrophoresis or isoelectric focusing demonstrates that at least 95% of the AP contains PI-glycan. Two-dimensional gel electrophoresis reveals two precursors of the mature AP. One of these does not bind an antibody against the Trypanosoma variable surface glycoprotein cross-reacting determinant and probably does not contain PI-glycan. This precursor had a shorter half-life than the more prominent PI-glycan-containing precursor in pulse-chase experiments, suggesting a precursor-product relationship between the two proteins. These data demonstrate that BeWo AP is the product of a gene normally expressed in testis, thymus, and germ cells, but not in placenta. Thus, the expression of BeWo AP results from the repression of the PLAP gene and derepression of the germ cell AP gene and, as such, the expression is ectopic. The BeWo AP (Nagao isozyme) is modified with PI-glycan that is added soon after translation, not cotranslationally.
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PMID:Expression of a Nagao-type, phosphatidylinositol-glycan anchored alkaline phosphatase in human choriocarcinomas. 216 49

The immunohistological expression of placental alkaline phosphatase (PLAP) and PLAP-like enzyme was studied in frozen sections from a wide variety (n = 254) of normal and malignant tissues using monoclonal antibodies reactive with PLAP (H317) and PLAP/PLAP-like enzyme (H17E2; H315). PLAP/PLAP-like reactivity was seen in normal thymus, and foetal and neonatal testis, and in 21 out of 22 malignant germ cell tumours (GCTs), but was also found in normal endocervix, normal Fallopian tube and in 28 out of 167 non-GCTs (particularly in ovarian and proximal gastrointestinal tract tumours). Positivity for true PLAP (as demonstrated with H317) was seen in term placenta, in endocervix, and in Fallopian tube (but not in other normal tissues) and was commonly found in ovarian and proximal gastrointestinal tract tumours. Reactivity with H317 was unusual in malignant GCTs (2 out of 22 cases). These findings confirm that PLAP/PLAP-like positivity is a highly sensitive immunohistological marker for malignant GCTs, but one which by itself is of only moderate specificity. Furthermore, expression of true PLAP is rare in GCTs and favours instead an origin from the ovary or proximal gastrointestinal tract. The results also indicate that the predominant heat-stable alkaline phosphatase species in normal foetal and neonatal testis, and in thymus has a similar immunohistological profile to that found in malignant GCTs, and is a PLAP-like enzyme ("germ cell alkaline phosphatase") distinct from true PLAP. The occurrence of this marker in GCTs would appear to reflect increased eutopic production of an enzyme present in trace amount in corresponding normal tissues rather than a genuine example of ectopic expression.
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PMID:The expression of placental alkaline phosphatase (PLAP) and PLAP-like enzymes in normal and neoplastic human tissues. An immunohistological survey using monoclonal antibodies. 217 80

Placental alkaline phosphatase (the PLAP-like isoenzyme) and liver alkaline phosphatase (LAP) were demonstrated immunohistochemically by use of monoclonal antibodies in the tumor cells of twelve seminomas and one seminoma metastasis. Intestinal alkaline phosphatase (IAP) was not found. The PLAP-like and LAP enzymes showed high catalytic activities compared to normal testis. This is the first occasion that LAP has been demonstrated by immunochemistry in seminoma cells. The results suggest that demonstration of these tumor enzymes may be useful markers for seminomas in histopathological specimens.
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PMID:Isoenzymes of alkaline phosphatases in seminomas. An immunohistochemical and biochemical study. 224 72

The placental alkaline phosphatase was purified by immunoaffinity chromatography from ovarian epithelial tumours to homogeneity. Up to 40% of the catalytical phosphatase activity in these tumours was derived from this placental type alkaline phosphatase (PLAP). The purified enzyme were similar to those of PLAP, whereas the PLAP-like isozyme was more heat-stable and resistant to 8 M urea than PLAP. The amino terminal sequence of the PLAP-like enzyme demonstrated heterogeneity at position three in the N-terminal end compared with PLAP. Phenyl-Sepharose affinity chromatography and different lectin chromatographies demonstrated the tumour-derived enzyme to be microheterogeneous, both with regard to concanavalin A binding and hydrophobicity properties.
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PMID:Purification and characterisation of the placental-like alkaline phosphatase from ovarian epithelial tumours. 238 81

Seminomas and control tissues were analyzed for several tumor markers. Very high levels of placental alkaline phosphatase (PLAP)-like enzyme levels were found in all 18 seminomas studied. The majority of the seminomas were of phenotype I, thus differing from palcental PLAP. The mean amount of enzyme protein as measured by monoclonal antibodies, was 100 times higher than in non-malignant tissues and 10 times lower than in placental tissue. The specific enzymatic activity in seminomas was about half of that observed in placenta. Similarly, the specific activity of PLAP-like enzymes in sera of patients with seminoma was only about half of that found in pregnancy sera. HCG was strongly elevated in 3 seminomas, but not obviously related to PLAP. Thirteen of the 17 pure seminomas had HCG over 100 IU/g, which was not seen in normal testes. Liver alkaline phosphatase (LAP) and intestinal alkaline phosphatase (IAP) were high in seminomatous tissues, the mean increases being 60-fold and 20-fold, respectively. The highest IAP levels were found in 2 yolk-sac tumors. Ferritin was moderately elevated in seminomas, but high in several control tissues. Carcinoembryonic antigen (CEA) was not elevated and alpha-fetoprotein (AFP) was not detected at all in pure seminomas. A decrease in carbohydrate antigen 50 (CA-50) content was noted in seminomas as compared to normal testes, yolk-sac tumors and choriocarcinomas. Defects in tumor-related enzymes may account for increase of PLAP and decrease of CA-50.
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PMID:Patterns of seminoma tissue markers and deletions. 244

The four known isozymes of the human alkaline phosphatase (ALP) were detected by isoelectric focusing in extracts of various types of germ cell tumors, three related cell lines, and their precancerous elements (atypical germ cells). In seminoma, placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (PLAP-like) could be separated by isoelectric focusing following isolation by immunoaffinity. The occurrence of both isozymes in seminoma could explain partial heat sensitivity and variation in electrophoretic patterns of the seminoma isozyme frequently observed upon starch gels, in comparison to the normal placental phenotype. The four ALP isozymes are produced not only in germ cell tumors, but already in precancerous tissues. Quantitative analysis showed that the amount of the four isozymes varies in parallel in the tumors tested. Maximal expression was found in seminoma. The relation between ALP gene overexpression and gene amplification by polyploidy of chromosomes 1 and 2 in these lesions is discussed. On the other hand, the ectopic expression of intestinal alkaline phosphatase and PLAP associated with overexpression of PLAP-like in tumor cells as well as in their precancerous stage indicates gene activation by some unknown mechanisms, probably a regulatory process affecting the three tissue-specific ALP genes simultaneously.
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PMID:Alkaline phosphatase isozymes in human testicular germ cell tumors, their precancerous stage, and three related cell lines. 254 14


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