Effect of metal ions on the secondary structure and activity of calf intestine phosphatase.
Cobalt is an essential microelements in many biological processes involving enzymatic activity. We found that Zn2+ and Mg2+, which are in the active site of native calf intestine alkaline phosphatase (CIP), can be replaced by Co2+ directly in solution. The effect of Co2+ concentration on the substitution reaction was examined at ratios of [Co2+]/[CIP] from 0:1 to 8:1. The quantity of Zn2+ in CIP decreased progressively as the ratio was increased, but the amount of Mg2+ changed in irrregular fashion. A series of active site models of the reaction mechanism of CIP are proposed. Low pH was found to promote the replacement of Mg2+ by Co2+. To understand how the substitution affects the enzyme, we also solved the secondary structure of CIP after reaction with Co2+ in different conditions.
Chen
Fengjuan
F
College of Chemistry and Chemical Engineering and State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, PR China.
Liu
Guoqi
G
Xu
Zhihong
Z
Zeng
Zhengzhi
Z
D000469:Alkaline Phosphatase / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D003035:Cobalt / Q000378:metabolism / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D020450:Heavy Ions; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000201:enzymology; D008670:Metals / Q000494:pharmacology*; D008954:Models, Biological; D017433:Protein Structure, Secondary / Q000187:drug effects
D008670:Metals; D003035:Cobalt; D000469:Alkaline Phosphatase