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Hydrazone formation of 2,4‐dinitrophenylhydrazine with pyrroloquinoline quinone in porcine kidney diamine oxidase
Author(s) -
van der Meer R.A.,
Jongejan J.A.,
Frank J.,
Duine jzn,
Duine J.A.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81350-3
Subject(s) - pyrroloquinoline quinone , diamine oxidase , hydrazone , chemistry , diamine , quinone , biochemistry , stereochemistry , polymer chemistry , enzyme , cofactor
Homogeneous diamine oxidase (EC 1.4.3.6) from porcine kidney was treated with the inhibitor 2,4‐dinitro‐phenylhydrazine (DNPH). The coloured compounds formed were detached with pronase and purified to homogeneity. When the reaction with DNPH was conducted under an O 2 atmosphere, the product (obtained in a yield of 55%) was the C(5)‐hydrazone of pyrroloquinoline quinone (PQQ) and DNPH, as revealed by its Chromatographie behaviour, absorption spectrum and 1 H‐NMR spectrum. Only 6% of this hydrazone was formed under air, the main product isolated being an unidentified reaction product of DNPH with the enzyme. Porcine kidney diamine oxidase is the second mammalian enzyme shown to have PQQ as its prosthetic group. In view of the requirements for hydrazone formation with DNPH, it is incorrect to assume that inhibition of this type of enzymes with common hydrazines is simply due to blocking of the carbonyl group of its cofactor.