P. Bouvrette et al., AMPEROMETRIC BIOSENSOR FOR DIAMINE USING DIAMINE OXIDASE PURIFIED FROM PORCINE KIDNEY, Enzyme and microbial technology, 20(1), 1997, pp. 32-38
Diamine oxidase was purified over 2300-fold from porcine kidney to a s
pecific activity of 1 U mg(-1). The final preparation exhibited a sing
le 103 kDa protein band and contained relatively large amounts of Asx
and Glx acidic residues. When stored at -80 degrees C, soluble enzyme
retained its original catalytic activity for at least five months. The
optimal pH and temperature of the enzyme immobilized by intramolecula
r cross-linking via gill taraldehyde activation and deposited onto a p
reactivated nylon membrane were 7.4 and 60 degrees C with cadaverine a
s substrate. The apparent K-m(n) values (Michaelis-Menten constants) o
f immobilized diamine oxidase with histamine, putrescine, and cadaveri
ne as substrates were estimated to be 0.27. 3.2, and 0.64 mM, respecti
vely. Artificial mediators such as ferrocene derivatives, 2,6-dichloro
phenolindophenol, potassium ferricyanide and 4-aminodiphenylamine were
nor observed to facilitate electron transfer from the reduced enzyme
to the electrode. The biosensor using the immobilized diamine oxidase
and a platinum working electrode (poised at +700 mM vs Ag/AgCl for det
ermination of hydrogen peroxide released from the enzymatic oxidation)
was linear up to 6 mM histamine, cadaverine, or putrescine with a low
er detection limit of 25 mu M. Each analysis could be performed in 3 m
in including washing and time for the current to return to baseline. T
he enzyme membranes were stable at 5 degrees C for at least two months
and could be used for more than 60 repeated analyses without signific
ant loss of sensitivity. (C) 1997 by Elsevier Science Inc.