PMID: 2606Feb 25, 1976

31P NMR of phosphate and phosphonate complexes of metalloalkaline phosphatases.

The Journal of Biological Chemistry
J F ChlebowskiJ E Coleman


31P NMR spectra of phosphate and phosphonate complexes of Escherichia coli alkaline phosphatase have been obtained by Fourier transform NMR methods. One equivalent of P1i, bound to Zn(II) alkaline phosphatase, pH 8, gives rise to a single 31P resonance 2 ppm downfield from that for Pi, and assignable to the noncovalent complex, E-P. Inorganic phosphate in excess of 1 eq per enzyme dimer gives rise to a resonance at the position expected for free Pi. At pH 5.1, a second resonance appears 8.5 ppm downfield from that for free Pi, and is assignable to the covalent complex, E-P. The large downfield shift suggests that the enzyme phosphoryl group is highly strained with an O-P-O bond angle of under 100 degrees.

Related Concepts

Alkaline Phosphatase
Binding Sites
Hydrogen-Ion Concentration
In Vivo NMR Spectroscopy
Phosphorus Isotopes

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