Spectroscopic and kinetics studies of the inhibition of pig kidney diamine oxidase by anions

Document Type

Article

Abstract

The role of copper in pig kidney diamine oxidase has been probed by examining the effects of potential Cu(II) ligands on the spectroscopic and catalytic properties of the enzyme. In the presence of azide and thiocyanate, new absorption bands are evident at 410 nm (epsilon = 6300 M-1 cm-1) and 365 nm (epsilon = 3000 M-1 cm-1), respectively. These bands are assigned as ligand-to-metal charge-transfer transitions, N3-/SCN- leads to Cu(II). One anion/Cu(II) is coordinated in an equitorial position. Anion binding can be completely reversed by dialysis. The equilibrium constants for diamine oxidase-anion complex formation are 134 M-1 (N3-) and 55 M-1 (SCN-). Azide and thiocyanate are linear uncompetitive inhibitors with respect to the amine substrate when O2 is present at saturating concentrations. Taken together, the data are consistent with a functional role for Cu(II) in diamine oxidase catalysis.

Medical Subject Headings

Amine Oxidase (Copper-Containing) (antagonists & inhibitors); Animals; Anions; Azides (pharmacology); Kidney (enzymology); Kinetics; Spectrophotometry; Swine; Thiocyanates (pharmacology)

Publication Date

4-10-1983

Publication Title

The Journal of biological chemistry

ISSN

0021-9258

Volume

258

Issue

7

First Page

4245

Last Page

8

PubMed ID

6403525

This document is currently not available here.

Share

COinS