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PubMed1997

Comparison of total alkaline phosphatase and three assays for bone-specific alkaline phosphatase in childhood and adolescence.

We compared serum levels of total alkaline phosphatase (TAP) and bone-specific alkaline phosphatase (BAP) as determined by three different assays (lectin affinity electrophoresis, immunoradiometric assay, enzyme-linked immunosorbent assay) in subjects aged 5-20 years suffering from X-linked hypophosphatemic rickets (n = 14), chronic renal failure (n = 10) and chronic cholestatic liver disease (n = 16). Results were compared to controls of the same age and were expressed as standard deviation scores (SDS). TAP correlated significantly with BAP (r > 0.9 for each assay; p < 0.001) in controls. In children with cholestatic diseases, TAP (median SDS + 2.0) was elevated, but BAP, as measured by the electrophoretic assay, was within the reference range for most patients (median SDS: -0.4; p = 0.003 for the difference between the median SDS of TAP and BAP). In contrast, results for BAP as determined by the two immunoassays were not significantly different from TAP in any of the three patient groups (p > 0.05 in each group for both assays). In this study, the two immunoassays did not have a detectable advantage over lectin affinity electrophoresis in the determination of BAP.

Adolescent↗
PubMed1988

An enzymatic marker in mothers of trisomy 21 children: neutrophil alkaline phosphatase.

Neutrophil alkaline phosphatase (NAP) from 12 mothers of normal children was investigated and the results compared to those of 7 mothers with trisomy 21 offsprings, in an attempt to determine a parental molecular change in this chromosomal abnormality. The biochemical properties of the enzyme were analyzed by the procedures of isoenzyme characterization, i.e. enzyme assays, thermostability, inhibition patterns and slab gel electrophoresis. Immunological properties were determined on 5 samples from normal mothers and on the same sample number of mothers with affected children. In these latter NAP showed characteristics that were to some extent different from the ones of normal controls. The following changes were observed: highly significant loading of membrane and nucleus pellets in NAP activity, poor effect of inhibitors on thermostable component and immunodepletion measured by a significant decrease of the normal affinity for antiliver and antiplacental alkaline phosphatase antisera. These findings are discussed in the light of our knowledge of alkaline phosphatase isoenzymes.

Adult↗
PubMed1985

[Biochemical characterization of a high-molecular weight alkaline phosphatase in a patient with cholangiocarcinoma (alpha-1 alkaline phosphatase)].

The authors analysed the alkaline phosphatases present in the serum of a patient with cholangiocarcinoma. The electrophoretic analysis on cellulose acetate revealed two bands of AP activity in positions alpha 1 and alpha 2. The more anodic of the isoenzymes of AP presented most of the features of the high molecular weight isoenzyme found in human bile, except that it was non-competitively inhibited by L-homoarginine. This feature, which distinguishes this isoenzyme form the biliary isoenzyme of AP, indicates the existence of another type of high molecular weight isoenzyme present in malignant hepatic diseases.

Adenoma, Bile Duct↗
PubMed1975

Disc electrophoresis of turkey serum alkaline phosphatase isoenzymes using polyacrylamide gel. 2. Turkey serum alkaline phosphatase zymograms.

The isoenzymes of alkaline phosphatase (akp) in turkey serum were separated by disc electrophoresis using polyacrylamide gel as the supporting medium Test subjects consisted of 103 turkeys maintained for the "Vibrator" condition at Michigan State University; and 46 female turkey of the Nicholas Broad Breasted White egg laying strain. Thirteen distinct akp bands were isolated. The 13 bands were observed to occur in 13 different patterns, each pattern being classified as a separate zymogram. Specific types of zymograms were detected for "Vibrator" birds vs. Nicholas strain; females vs, males; high intensity egg production vs. low intensity egg production and molting vs. laying.

Alkaline Phosphatase↗
PubMed1996

Regulation of alkaline phosphatase: implications for calcium pyrophosphate dihydrate crystal dissolution and other alkaline phosphatase functions.

OBJECTIVE: Alkaline phosphatase (ALP), an enzyme with pyrophosphatase (PPiase) activity can dissolve calcium pyrophosphate dihydrate (CPPD) crystals. We studied the effects of enzyme inhibitors such as bisphosphonates, orthovanadate, calcium, cadmium, and ascorbic acid on PPiase activity of ALP as well as on phosphate ester hydrolysis (Pase) activity and compared these effects to those on CPPD crystal dissolution. METHOD: An in vitro model system for crystal enzyme interaction was used to assess CPPD crystal dissolution. RESULTS: Bisphosphonates inhibited ALP Pase activity more than ALP PPiase activity at the same concentrations. Calcium inhibited ALP PPiase activity, but not ALP Pase activity. Orthovanadate and cadmium inhibited ALP PPiase activity more than ALP Pase at the same concentrations. The inhibition rates of ALP PPiase at the same concentrations were orthovanadate > cadmium > calcium. Although ALP Pase activity was not inhibited, at high concentrations, ascorbic acid slightly inhibited ALP PPiase activity. Bisphosphonates at high concentrations inhibited ALP CPPD crystal dissolution. The strong inhibitory effects of bisphosphonates on ALP CPPD crystal dissolution compared to those on ALP PPiase activity suggest that bisphosphonates inhibit crystal dissolution by their affinity for the CPPD crystal surface. Calcium, orthovanadate, and cadmium inhibited ALP CPPD dissolution. The inhibition rates of ALP CPPD dissolution at the same concentrations were cadmium > calcium > orthovanadate. Ascorbic acid at high concentrations enhanced ALP CPPD dissolution. CONCLUSION: These effects of different inhibitors on ALP PPiase and CPPD dissolution suggest that ALP CPPD crystal dissolution depends on binding of ALP CPPD crystals as well as the PPiase activity of the bound ALP. Because of its ubiquitous and broad phosphatase activity including PPiase activity, ALP may have a critical role in cell energy metabolism.

Alkaline Phosphatase↗
PubMed2006

Positive placental staining for alkaline phosphatase corresponding with extreme elevation of serum alkaline phosphatase during pregnancy.

Placental ALP (ALP(h)) is a membrane-anchored, heat-stable enzyme produced by the syncytiotrophoblast. We report a case of a patient presenting in the third trimester with extreme increased levels of ALP(h). A 40-year-old woman, gravida 2, para 1, was admitted to the high risk pregnancy unit at 30 weeks of gestation for evaluation of an incidental finding of marked isolated elevation in serum ALP(h). Blood tests obtained at admission revealed a marked elevation of serum ALP level up to 1,194 u/l (reference 35-104 u/l). At 36 weeks of gestation, the patient was admitted with preterm premature rupture of membranes. Due to breech presentation, a cesarean delivery was performed. An immunoperoxidase stain was done for placental alkaline phosphatase, which was positive in the majority of chorionic trophoblastic cells. No evidence of inflammation was detected in the placental chorionic plate. Thus, isolated elevation in placental ALP may be linked to a subsequent preterm delivery.

Adult↗
PubMed1991

Bacillus subtilis alkaline phosphatases III and IV. Cloning, sequencing, and comparisons of deduced amino acid sequence with Escherichia coli alkaline phosphatase three-dimensional structure.

Bacillus subtilis has an alkaline phosphatase multigene family. Two members of this gene family, phoAIII and phoAIV, were cloned, taking advantage of in vitro constructed strains containing a plasmid insertion within one or the other of the structural genes. The DNA sequences of the two genes showed approximately 64% identity at the DNA level and 63% identity in the deduced primary amino acid sequences. The phoAIII and phoAIV genes code for predicted proteins of 47,149 and 45,935 Da, respectively. Comparison of the deduced primary amino acid sequence of the mature proteins with other sequenced alkaline phosphatases from Escherichia coli, yeast, and humans shows 25-30% identity. Based on the refined crystal structure of E. coli alkaline phosphatase, it appears that the active site and the core of the structure are retained in both Bacillus alkaline phosphatases. However, both proteins are truncated at the amino terminus compared with other mature alkaline phosphatases, three sizable surface loops of E. coli are deleted, and a minidomain is replaced with a larger domain in the model. Neither Bacillus alkaline phosphatase sequenced contains any cysteine residues, an amino acid implicated in intrachain disulfide bond formation in other alkaline phosphatases.

Alkaline Phosphatase↗
PubMed1986

Radioimmunodetection of human choriocarcinoma xenografts by monoclonal antibody to placental alkaline phosphatase.

Placental alkaline phosphatase (PLAP)-specific monoclonal antibody (MAb) 11-D-10, which did not react with other isoenzymes of alkaline phosphatase (AP), was raised by a hybridoma technique. MAb 11-D-10 was radiolabeled and administered to athymic mice bearing human choriocarcinoma containing PLAP. This antibody was found to be more specifically localized in tumor tissue as compared to normal tissues. The tissue-to-blood ratio (T/B ratio) of MAb 11-D-10 in tumor tissue increased from 1.38 at 2 days to 2.51 at 5 days after administration. On the other hand, the T/B ratios of isotype control non-immunized IgM in tumor tissue were 0.72 and 0.87 at 2 days and 5 days after administration, respectively. 131I-labeled MAb 11-D-10 was administered to athymic mice bearing choriocarcinomas of various sizes and various PLAP contents to examine the effect on the radioimage of the differences in tumor size and PLAP content. Tumors less than 0.3 cm in diameter could be imaged clearly by gamma-scintigraphy without blood pool image subtraction. The strength of the radioimage correlated fairly well with PLAP content.

Alkaline Phosphatase↗
PubMed1997

Bone to total alkaline phosphatase ratios improve sensitivity and specificity of bone alkaline phosphatase immunoassays.

OBJECTIVES: Evaluate the ability of two bone alkaline phosphatase (ALPB) immunoassays (Ostase, Hybritech Inc and Alkphase-B, Metra Biosystems) to clinically differentiate between osseous and non-osseous ALP sources. DESIGN AND METHODS: Specimens from patients with either liver or bone disease (Paget's disease or metastatic cancer) were analyzed by both methods. RESULTS: There was a good correlation between these two assays. Values for ALPB, whether determined as a concentration by the Ostase assay or as an activity by the Alkphase-B assay, were similar for subjects with liver disease or bone disease. However, total ALP (ALPT) activity was higher in liver disease compared to bone. When ALPB was expressed in relation to ALPT, ratios were significantly greater in subjects with bone disease than in those with liver disease. ALPB/ALPT ratios improved the specificity of the Ostase assay from 52% to 86% and the Alkphase-B assay from 58% to 74%. CONCLUSIONS: These two ALPB assays have good analytical performance and their clinical utility can be enhanced by expressing ALPB values in relation to ALPT activity.

Adult↗
PubMed1975

Phosphatases XII. Isoenzymes of alkaline phosphatase and radionuclear investigation (85Sr) of patients with neoplastic affection of the skeleton.

In a group of 30 patients with neoplastic processes, 13 were found to have a significantly increased serum alkaline phosphatase activity. This finding correlated with the results of investigation with 85Sr in 7 patients, but owing to a concomitant hepatal symptomatology, it proved of differential diagnostic value in only one of them. On the other hand, the activity of bone isoenzyme of alkaline phosphatase was significantly altered in 15 patients. In 14 of them the increase in bone isoenzyme activity corresponded to an X-ray and a radionuclear finding of a tumor process in the bones. This activity was within the normal range of values in only one patient with a positive result of the 85Sr investigation. An agreement between the results of determination of bone isoenzyme activity of alkaline phosphatase and those of radionuclear investigations was found in 27 patients. In addition, a correlation was established between the increased activity of bone isoenzyme and that of intestinal isoenzyme of alkaline phosphatase. Enzyme investigation can be suitably utilized, alongside radionuclear examination, for early detection of a bone process.

Adult↗
PubMed2000

Reversal of malignant phenotype in human osteosarcoma cells transduced with the alkaline phosphatase gene.

Alkaline phosphatases are a family of glycoproteins that are able to hydrolize various monophosphate esters at a high pH optimum. Liver/bone/kidney (L/B/K) alkaline phosphatase (ALP) is one of the four major isoenzymes that belong to this family. Apart from its role in normal bone mineralization, other functions of L/B/K ALP remain obscure, both in physiological and in neoplastic conditions, including the bone-forming tumor osteosarcoma. In this study, we transfected the U-2 OS osteosarcoma cell line, which does not show any basal expression of this enzyme, with the full-length gene of L/B/K ALP, and analyzed the in vitro and in vivo features of four transfectants showing different expression of L/B/K ALP. A reduced in vitro ability to invade Matrigel and to grow in a semi-solid medium, together with a lower tumorigenic and metastatic ability in athymic mice, was found to be associated with a high level of cell surface L/B/K ALP activity. Moreover, L/B/K ALP transfectants showed a reduced secretion of matrix metalloproteinase-9 enzyme. These findings indicate a loss of aggressiveness of osteosarcoma cells after the expression of L/B/K ALP on their surface and suggest a new role for this enzyme.

Alkaline Phosphatase↗
PubMed1981

A soluble alkaline phosphatase from Bacillus licheniformis MC14. Histochemical localization, purification, characterization and comparison with the membrane-associated alkaline phosphatase.

Growth conditions affect the quantity and distribution of alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) in Bacillus licheniformis MC14. The soluble alkaline phosphatase, which has been found in biochemical localization studies between the cell wall and cell membrane (Glynn, J.A., Schaffel, S.D., McNicholas, J.M. and Hulett, F.M. (1977) J. Bacteriol. 129, 1010-1019), was localized via electron microscope histochemistry in cells cultured under conditions which result in increased quantities of this activity. This soluble alkaline phosphatase was stabilized with 20% glycerol and purified to homogeneity as determined by sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis. The purified enzyme is soluble in dilute buffer. This soluble alkaline phosphatase has been characterized and compared to the membrane-associated alkaline phosphatase from this organism.

Alkaline Phosphatase↗