scholarly journals The effect of 1,25(OH)2D3 on alkaline phosphatase in osteoblastic osteosarcoma cells.

1982 ◽  
Vol 257 (7) ◽  
pp. 3362-3365 ◽  
Author(s):  
R J Majeska ◽  
G A Rodan
Keyword(s):  
Alkaline Phosphatase ◽  
Osteosarcoma Cells ◽  
Osteoblastic Osteosarcoma

Individual and combined effects of intact PTH, amino-terminal, and a series of truncated carboxyl-terminal PTH fragments on alkaline phosphatase activity in dexamethasone-treated rat osteoblastic osteosarcoma cells, ROS 17/2.8

1993 ◽  
Vol 128 (4) ◽  
pp. 367-372 ◽  
Author(s):  
Chizu Nakamoto ◽  
Hisamitsu Baba ◽  
Masaaki Fukase ◽  
Kiichiro Nakajima ◽  
Terutoshi Kimura ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Combined Effects ◽  
Osteosarcoma Cells ◽  
Intact Pth ◽  
Amino Terminal ◽  
Terminal Amino ◽  
Carboxyl Terminal ◽  
Osteoblastic Osteosarcoma

The individual and combined effects of intact PTH, amino-terminal, and a series of truncated carboxyl-terminal PTH fragments on alkaline phosphatase activity were examined in dexamethasone-treated rat osteoblastic osteosarcoma cells ROS 17/2.8. Dexamethasone-induced alkaline phosphatase activity was inhibited not only by hPTH(1–84) and amino-terminal PTH fragment hPTH(1–34), but also by carboxyl-terminal PTH fragment hPTH(69–84) in a dose-related fashion. At 10−7 mol/1, hPTH(1–84) completely abolished dexamethasone-induced alkaline phosphatase activity, while hPTH(1–34) and hPTH(69–84) reduced alkaline phosphatase activity to 0.16±0.02 and 0.80±0.03 fold, respectively, of the control value obtained in the absence of PTH peptides. The combination of hPTH(1–34) and hPTH(69—84) resulted in reduction of alkaline phosphatase activity to the level obtained by hPTH(1-84). The shorter carboxyl-terminal PTH fragment hPTH(71–84) did not affect alkaline phosphatase activity or modulate the action of hPTH(1–34). The longer carboxyl-terminal PTH fragment hPTH(53-84) stimulated alkaline phosphatase activity up to 1.23±0.03 fold and partially blunted the inhibitory effect of hPTH(1–34) on alkaline phosphatase activity. These findings suggest that carboxyl-terminal PTH fragments could exert diverse effects on the target cells, depending on the length of deletion of amino-terminal amino acids of PTH molecule, and interact with amino-terminal PTH fragment. The two amino-terminal amino acids of hPTH(69–84) and the 53–68 portion of hPTH(53–84) might be responsible for the respective inhibitory and stimulatory effects of the peptides on alkaline phosphatase activity.

Incorporation of human liver and placental alkaline phosphatases into liposomes and membranes is via phosphatidylinositol

1990 ◽  
Vol 68 (9) ◽  
pp. 1112-1118 ◽  
Author(s):  
Lee Kihn ◽  
Dorothy Rutkowski ◽  
Robert A. Stinson
Keyword(s):  
Alkaline Phosphatase ◽  
Phospholipase C ◽  
Human Liver ◽  
Red Cell ◽  
Osteosarcoma Cells ◽  
Alkaline Phosphatases ◽  
Membrane Anchor ◽  
Gradient Gel Electrophoresis ◽  
Triton X ◽  
Phosphatidylinositol Phospholipase C

As assessed by incorporation into liposomes and by adsorption to octyl-Sepharose, the integrity of the membrane anchor for the purified tetrameric forms of alkaline phosphatase from human liver and placenta was intact. Any treatment that resulted in a dimeric enzyme precluded incorporation and adsorption. An intact anchor also allowed incorporation into red cell ghosts. The addition of hydrophobic proteins inhibited incorporation into liposomes to varying degrees. Alkaline phosphatase was 100% releasable from liposomes and red cell ghosts by a phospholipase C specific for phosphatidylinositol. There was no appreciable difference in the rates of release of placental and liver alkaline phosphatases, although both were approximately 250 × slower in liposomes and 100 × slower in red cell ghosts than the enzyme's release from a suspension of cultured osteosarcoma cells. Both enzymes were released by phosphatidylinositol phospholipase C as dimers and would not reincorporate or adsorb to octyl-Sepharose. However, the enzyme incorporated, resolubilized by Triton X-100, and cleansed of the detergent by butanol treatment was tetrameric by gradient gel electrophoresis, was hydrophobic, and could reincorporate into fresh liposomes. A monoclonal antibody to liver alkaline phosphatase inhibited the enzyme's incorporation into liposomes, and abolished its release from liposomes and its conversion to dimers by phosphatidylinositol phospholipase C.Key words: alkaline phosphatase, liposome, phosphatidylinositol, membrane anchor.

Reference standards for quantification of skeletal alkaline phosphatase activity in serum by heat inactivation and lectin precipitation

1993 ◽  
Vol 39 (9) ◽  
pp. 1878-1884 ◽  
Author(s):  
J R Farley ◽  
S L Hall ◽  
S Herring ◽  
C Libanati ◽  
J E Wergedal
Keyword(s):  
Alkaline Phosphatase ◽  
Alkaline Phosphatase Activity ◽  
Concanavalin A ◽  
Wheat Germ ◽  
Bone Cells ◽  
Heat Inactivation ◽  
Osteosarcoma Cells ◽  
Con A ◽  
Alp Activity ◽  
Skeletal Alkaline Phosphatase

Abstract Putative standards of skeletal alkaline phosphatase (ALP) (from bone, bone cells, osteosarcoma cells, and Pagetic serum) and hepatic ALP (from cholestatic serum and bile) were used to compare three methods for quantifying skeletal ALP activity in serum: heat inactivation, precipitation with wheat germ agglutinin (WGA), and precipitation with concanavalin A (Con A). All the skeletal ALP standards were similarly sensitive to heat inactivation, as were the hepatic ALP standards. Heat inactivation separated skeletal from hepatic ALP by a 50% difference in remaining ALP activities (e.g., 23% and 74% remaining skeletal and hepatic ALP activities after 30 min at 52 degrees C). Differential precipitations with WGA and with Con A were less efficient at separating skeletal from hepatic ALP (maximum differences of < 30% remaining ALP activity). Although both types of hepatic ALP standard (cholestatic serum and bile) were precipitated with similar efficiencies by WGA and Con A, the skeletal ALP standards were not (e.g., at 2.7 g/L, WGA precipitated 78-86% of the ALP activity in Pagetic serum, but only 49% of the ALP activity in extracts of human bone). These data suggest that heat inactivation is preferable to precipitation with WGA or Con A for quantifying skeletal ALP activity in serum: it better separates skeletal from hepatic ALP activity and is not sensitive to glycosyl heterogeneity.

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