Kinetic studies on the membrane form of intestinal alkaline phosphatase
Braz. j. med. biol. res
;
27(12): 2859-62, Dec. 1994. tab, graf
Article
Dans Anglais
| LILACS
| ID: lil-153284
RESUMO
We have purified different membrane and soluble forms of alkaline phosphatase from human placenta and bovine intestine. The enzymes will be used as markers in immunoconjugates and/or as model for membrane enzyme studies. The membrane formof alkaline phosphatase extracted from bovine intestine was purified on Q-Sepharose and on L-histidyldiazobenzylphosphonic acid-agarose columns to remove phosphodiesterase activity. The purified enzyme had a molecular mass of 61 kDa, Km of 1208 µM, and Vmax 240 µmol pNP/min when assayed in 1 M diethanolamine, 0.5 mM MgCl2 buffer, pH 9.8, containing 10 to 2250 µM of pNPP at 37§C. In the present investigation we studied the effect of salts and inositol derivatives on this enzyme activity, which was found to depend on 0.5 mM Mg2+, and to be fully inhibited by 1.2 mM Hg2+. Vanadate (0.5 mM) and Zn2+ (0.5 mM) reduced the Km value by 43 percent and 84 percent, respectively. Inositol (2 mM) and inositol-2-monophosphate (2 mM) reduced the activity by 23 percent and 17 percent. Inositol-1-monophosphate (0.5 mM) and cyclic-inositol-(12)-monophosphate (0.5 mM) enhanced their Km value by at least 30 percent compared to p-nitrophenylphosphate
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Indice:
LILAS (Amériques)
Sujet Principal:
Phosphatase alcaline
/
Inositol
/
Intestins
Limites du sujet:
Animaux
/
Humains
langue:
Anglais
Texte intégral:
Braz. j. med. biol. res
Thème du journal:
Biologie
/
Médicament
Année:
1994
Type:
Article
/
Congrès et conférence
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