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Kinetic studies with alkaline phosphatase in the presence and absence of inhibitors and divalent cations
Author(s) -
Dean Rob L.
Publication year - 2002
Publication title -
biochemistry and molecular biology education
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 39
eISSN - 1539-3429
pISSN - 1470-8175
DOI - 10.1002/bmb.2002.494030060138
Subject(s) - chemistry , divalent , alkaline phosphatase , zinc , reaction rate , hydrolysis , enzyme , phosphate , inorganic chemistry , magnesium , cofactor , nuclear chemistry , medicinal chemistry , biochemistry , organic chemistry , catalysis
A very robust and inexpensive kinetic assay for determining rates of hydrolysis of p ‐nitrophenyl phosphate by the enzyme alkaline phosphatase is presented. The reaction increases in rate with increase in pH. The enzyme is competitively inhibited by the reaction products, uncompetitively inhibited by L ‐phenylalanine, and responds to the presence of two cofactors, magnesium and zinc ions. The reaction rate increases as Mg 2+ concentration is increased from 1–5 m M . With increasing Zn 2+ concentration, the reaction rate is stimulated and then depressed. Experimental work on the interaction between Mg 2+ and Zn 2+ in the reaction is suggested for more capable students.