Premium
Determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method
Author(s) -
GRANSTRÖM GÖSTA,
LINDE ANDERS
Publication year - 1975
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.1975.tb00450.x
Subject(s) - inorganic pyrophosphatase , odontoblast , chemistry , nuclear chemistry , layer (electronics) , radiochemistry , pyrophosphatases , dentistry , chromatography , biochemistry , medicine , dentin , enzyme , organic chemistry , pyrophosphate
— The enzyme inorganic pyrophosphatase (PP i ase, EC 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. The enzyme was incubated with 32 P‐pyrophosphate in tris‐HCl buffer at 37°C. The reaction was linear with time for at least 45 min, and the pH optimum was found to be 8.8, independent of the amount of pyrophosphate present. Heating the enzyme at 56°C inhibited the enzyme activity rapidly, Mg 2+ ions activated the enzyme by 15% at an ion concentration of 4 mM, while higher concentrations were inhibitory. Ca 2 + ions and PO 4 3− ions inhibited the enzyme at all concentrations. F‐ ions did not affect the PP i ase at concentrations below 8 mM, whereas higher concentrations had an inhibiting effect. Urea was found to inhibit the enzyme at concentrations above 1.5 M, while EDTA was a strong inhibitor at very low concentrations. The characteristics of PP i ase agree well with the properties of the enzyme non‐specific alkaline phosphatase (EC 3.1.3.1.) studied earlier.