Polyamine oxidases

Polyamine oxidase is a flavin-dependent peroxisomal enzyme involved in the degradation of polyamines to putrescine. This assay measures the conversion of /V -acetylspermidine to putrescine. 

Following derivatization with o-phthalaldehyde, TV1 -acetylspermidine, and putrescine are separated on a Beckman Ultrasphere ion-pair column (4.6 mm x 250 mm, 5 /urn). Solvent A was composed of 0.1 M sodium acetate and 10 mM octanesulfonic acid adjusted to pH 4.5 with acetic acid. Solvent B contained 0.2 M sodium acetate (pH 4.5)-acetonitrile (10 3, v/v) with 10 mM octanesulfonic acid. A linear gradient from 35% A and 65% B to 100% B was achieved in 10 minutes, followed by continued flow of solvent B for 15 minutes. The flow rate was 1 mL/min. Postminutes, column derivatization of polyamines with o-phthalaldehyde was accomplished with a pump. Fluorescence detection was used, with excitation and emission wavelengths of 340 and 455 nm. 

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Kamei et al. [45] separated spermine, spermidine, putrescine, and cadav-erine in an ion-pair reversed-phase LC system and detected the hydrogen peroxide formed in the reaction catalyzed by the enzymes putrescine oxidase and polyamine oxidase with POCL. The same analytes were determined in a later study [46], together with the acetyl derivatives. The sensitive determination of uric acid, selectively converted to hydrogen peroxide by uricase, has been investigated by several authors [37, 47],... 

The enzymes involved in the polyamine metabolic pathway have been the subject of intensive study, and a number of specific inhibitors for these enzymes have been designed as potential antitumor or antiparasitic agents [166]. Thus, a-difluoromethylornithine, has become a clinically useful agent [167]. Most of the studies involving inhibitors of polyamine metabolism have focused on enzymes involved in the biosynthetic pathway. Recently, there has been considerable interest generated in the enzyme spermidine/spermine-hT -acetyltrans-ferase enzyme (SSAT), the rate-limiting step in the back conversion of polyamines. SSAT, in conjunction with polyamine oxidase (PAO), allows for reversal of the biosynthetic pathway and attenuation of the levels of individual polyamines. 

Wang, Y, Murray-Stewart, T., Devereux, W., Hacker, A., Frydman, B., Woster, P.M. and Casero, R.A. Jr. (2003) Properties of purifled recombinant human polyamine oxidase, PAOhl/SMO. Biochemical and Biophysical Research Communications,... 

Binda, C., Mattevi, A. and Edmondson, D.E. (2002) Structure-function relationships in flavoenzyme-dependent amine oxidations. A comparison of polyamine oxidase and monoamine oxidase. The Journal of Biological Chemistry, 277, 23973-2397(>. 

Amine oxidases catalyze the oxidative deamination of both xenobiotic and biogenic amines, and thus have many critical biological functions. Two distinct classes differ in the nature of their prosthetic groups [1]. The flavin-(FAD flavin adenine dinucleotide)-dependent amine oxidases include monoamine oxidases (MAO A and B) and polyamine oxidases. Amine oxidases not containing FAD, the so-called semicarbazide-sensitive amine oxidases (SSAO), include both plasma amine oxidases and tissue amine oxidases. These contain quinonoid structures as redox cofactors that are derived from posttranslationally modified tyrosine or tryptophan side chains, topaoquinone frequently playing this role [2]. 

Polyamine oxidase (amine oxygen oxidoreductase, deaminating, flavin-containing), is also a FAD-dependent enzyme and has many similarities to MAO. It is responsible for the oxidation of the secondary amino group in such substrates as A/-acetyl spermine and spermidine in the biosynthesis of spermidine and putrescine [1,12], This enzyme will not be covered in this chapter. 

Amine oxidases catalyze the oxidation of amines, diamines, and polyamines. According to their ability to recognize one of those substrates preferentially, amine oxidases may be divided into monoamine oxidases, diamine oxidases, and polyamine oxidases, respectively. Several different enzymes fall into the amine oxidase class, and the classification of some of them still remains ambiguous. The term monoamine oxidase (flavin-containing, EC 1.4.3.4) was introduced to contrast with copper-containing amine oxidases (EC 1.4.3.6). 

Conditions for cytosolic incubations depend on the aim of the assay e.g. to cover specific enzymatic activity present in the cytosol. For this purpose it is essential to fortify the incubation medium with the specific cofactor for the reaction-if needed (Ekins 1999). (J> -Nicotinamide adenine dinucleotide (NAD) is needed for alcohol and aldehyde dehydrogenases, flavin adenine dinucleotide (FAD) for polyamine oxidase, P-nicotinamide adenine dinucleotide phosphate (NADPH) for Dihydropyrimidine dehydrogenase. Phase II reactions depend on PAPS (sulfotransferases,... 

Polyamine oxidases have been studied most extensively in cereal plants and have been shown to be extracellular enzymes located in the cell wall with a probable role in cell signalling (Smith, 1985). 

Isobe, K., Tani, Y., and Yamada, H., 1980, Crystallization and characterisation of polyamine oxidase from Penicillium chrysogenum, Agric. Biol. Chem. 44 2651fi2658. 

Kaur-Sawhney, R., H. E. Flores, A. W. Galston (1981), Polyamine Oxidase in Oat Leaves A Cell Wall Localized Enzyme, Plant Physiol. 68, 494-498. 

Polyamines (namely spermidine) are oxidatively deaminated not only by the action of copper amine oxidases. Flavin-containing polyamine oxidases (PAOs, EC 1.5.3.-) are also involved in their catabolism. An alternative grouping divides both above mentioned catabolic enzymes into those that act on the primary amino group of di- and polyamines (diamine oxidases) and those that act on the secondary amino group of polyamines (polyamine oxidases) [15], As suggested by Morgan, the latter should be further subdivided according to whether propane-1,3-diamine or 3-aminopropanal is the reaction product [16]. 

The exact nature of the reaction products of PAOs depends on the source of the enzyme [1]. Mammalian PAOs transform spermidine and spermine into putrescine and spermidine, respectively, plus 3-aminopropanal. By contrast, plant and bacterial polyamine oxidases... 

Fig. (6). The 3-D structure of monomeric FAD-containing polyamine oxidase from maize seedlings [ 18] completely differs from that of copper amine oxidases.

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