Open AccessOn the Nature of Chromophore in Pig Kidney Diamine Oxidase
Author(s) -
FINAZZI AGRÒ Alessandro,
GUERRIERI Pietro,
COSTA Maria Teresa,
MONDOVI Bruno
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11409.x
Subject(s) - diamine oxidase , chemistry , chromophore , phenylhydrazine , pyridoxal phosphate , pyridoxal , cycloserine , diamine , copper , chelation , photochemistry , transamination , enzyme , inorganic chemistry , biochemistry , medicinal chemistry , organic chemistry , cofactor , antibiotics
The nature of the 500‐nm chromophore in pig kidney diamine oxidase was investigated by absorption spectroscopy and fluorescence in the presence of various chelating or carbonyl‐specific reagents. From the spectroscopic measurements the following conclusions can be drawn. First, the 500‐nm absorption band is not due to copper, the reduction of which is not related to the disappearance of this band. Second, phenylhydrazine and cycloserine give rise, upon reaction with the enzyme, to absorptions very similar to those of a pyridoxal enzyme, aspartate aminotransferase. Third, these enzyme derivatives are unexpectedly non‐fluorescent. Copper removal, obtained after prolonged incubation of cycloserine‐treated enzyme in the presence of reducing and chelating agents, leads to a fluorescence similar to that of cycloserine‐aspartate transaminase. It is proposed that copper is coordinated to the postulated pyridoxal phosphate of diamine oxidase through the pyridine nitrogen.