scholarly journals QM/MM Analysis Suggests That Alkaline Phosphatase (AP) and Nucleotide Pyrophosphatase/Phosphodiesterase Slightly Tighten the Transition State for Phosphate Diester Hydrolysis Relative to Solution: Implication for Catalytic Promiscuity in the AP Superfamily

2011 ◽  
Vol 134 (1) ◽  
pp. 229-246 ◽  
Author(s):  
Guanhua Hou ◽  
Qiang Cui
Keyword(s):  
Alkaline Phosphatase ◽  
Transition State ◽  
Catalytic Promiscuity ◽  
Phosphate Diester ◽  
Nucleotide Pyrophosphatase

Usefulness of serum nucleotide pyrophosphatase and phosphodiesterase I activities in classifying liver disease.

1981 ◽  
Vol 27 (8) ◽  
pp. 1392-1396 ◽  
Author(s):  
H F Haugen ◽  
S Ritland ◽  
J P Blomhoff ◽  
H E Solberg ◽  
S Skrede
Keyword(s):  
Alkaline Phosphatase ◽  
Liver Disease ◽  
Discriminant Analysis ◽  
Clinical Routine ◽  
Extrahepatic Cholestasis ◽  
Nucleotide Pyrophosphatase ◽  
Different Types ◽  
Test Sets ◽  
Liver Tests

Abstract Nucleotide pyrophosphatase and phosphodiesterase I activities were determined in sera from 126 patients with different types of liver disease and in two additional groups of patients with intra- and extrahepatic cholestasis, respectively. Both activities probably represent the same enzyme, and were positively correlated with alkaline phosphatase, lipoprotein X, and several other tests reflecting cholestasis. Also, we found by discriminant analysis that tests for cholestasis frequently replaced the results of both enzymes. In some groups of liver disease, nucleotide pyrophosphatase and phosphodiesterase I were correlated with the concentrations of prealbumin and albumin. The sensitivity of phosphodiesterase I (and nucleotide phosphatase) is rather low when compared with alkaline phosphatase, and we do not recommend it for use in the clinical routine. Nevertheless, it appears to be of potential value for studies on classification of liver diseases, adding information to a panel of 20 commonly used "liver tests" by appearing in some of the best four test-sets for distinguishing between groups of liver disease by discriminant analysis.

scholarly journals A Model of the Transition State in the Alkaline Phosphatase Reaction

1999 ◽  
Vol 274 (13) ◽  
pp. 8351-8354 ◽  
Author(s):  
Kathleen M. Holtz ◽  
Boguslaw Stec ◽  
Evan R. Kantrowitz
Keyword(s):  
Alkaline Phosphatase ◽  
Transition State ◽  
Alkaline Phosphatase Reaction

scholarly journals Proteoliposomes Harboring Alkaline Phosphatase and Nucleotide Pyrophosphatase as Matrix Vesicle Biomimetics

2010 ◽  
Vol 285 (10) ◽  
pp. 7598-7609 ◽  
Author(s):  
Ana Maria S. Simão ◽  
Manisha C. Yadav ◽  
Sonoko Narisawa ◽  
Mayte Bolean ◽  
Joao Martins Pizauro ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Matrix Vesicle ◽  
Nucleotide Pyrophosphatase

Osteoblast tissue-nonspecific alkaline phosphatase antagonizes and regulates PC-1

2000 ◽  
Vol 279 (4) ◽  
pp. R1365-R1377 ◽  
Author(s):  
K. A. Johnson ◽  
L. Hessle ◽  
S. Vaingankar ◽  
C. Wennberg ◽  
S. Mauro ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Specific Activity ◽  
Bone Matrix ◽  
Pericellular Matrix ◽  
Wild Type ◽  
Matrix Mineralization ◽  
Inorganic Pyrophosphate ◽  
Nucleotide Pyrophosphatase ◽  
Tissue Nonspecific Alkaline Phosphatase ◽  
Calvarial Osteoblast

Tissue-nonspecific alkaline phosphatase (TNAP) is essential for bone matrix mineralization, but the central mechanism for TNAP action remains undefined. We observed that ATP-dependent 45Ca precipitation was decreased in calvarial osteoblast matrix vesicle (MV) fractions from TNAP−/− mice, a model of infantile hypophosphatasia. Because TNAP hydrolyzes the mineralization inhibitor inorganic pyrophosphate (PPi), we assessed phosphodiesterase nucleotide pyrophosphatase (PDNP/NTPPPH) activity, which hydrolyzes ATP to generate PPi. Plasma cell membrane glycoprotein-1 (PC-1), but not the isozyme B10 (also called PDNP3) colocalized with TNAP in osteoblast MV fractions and pericellular matrix. PC-1 but not B10 increased MV fraction PPi and inhibited 45Ca precipitation by MVs. TNAP directly antagonized inhibition by PC-1 of MV-mediated 45Ca precipitation. Furthermore, the PPi content of MV fractions was greater in cultured TNAP−/− than TNAP+/+ calvarial osteoblasts. Paradoxically, transfection with wild-type TNAP significantly increased osteoblast MV fraction NTPPPH. Specific activity of NTPPPH also was twofold greater in MV fractions of osteoblasts from TNAP+/+ mice relative to TNAP−/− mice. Thus TNAP attenuates PC-1/NTPPPH-induced PPigeneration that would otherwise inhibit MV-mediated mineralization. TNAP also paradoxically regulates PC-1 expression and NTPPPH activity in osteoblasts.

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