Methylamine oxidase

Mclntire, W. S., 1990, Methylamine oxidase from Arthrobacter PI, Methods in Enzymology, 188 227n235. 

Vanlersel, J.,Van der Meer, R. A., and Duine, J.A., 1986, Methylamine oxidase from Arthrobacter PI, a bacterial copper-quinoenzyme, Eur. J. Biochem. 161 4159419. 

J. V. lersel, R. A. van der Meer, and J. A. Duine, Methylamine oxidase from Athrobacter FI, a bacterial copper-quinoprotein amine oxidase, Eur. ]. Bio-chem., 161 415 (1986). 

In the amine oxidase from Escherichia coli, the topa quinone was confirmed by a detailed analysis of the cofactor dipeptide X-Asp [67] and the resonance Raman spectrometry of the enzyme and its derivatives[68,69]. The primary structure of the enzyme also contains the cofactor consensus sequence [70]. More bacterial genes were shown to encode proteins containing the topa quinone consensus sequence, such as amine oxidase from Klebsiella aerogenes [71], phenethylamine oxidase and histamine oxidase from Arthrobacter globiformis [72,73], and methylamine oxidase from Arthrobacter strain PI [74]. Amino acid sequences around the position of the cofactor for selected amine oxidases from various sources are given in Table 1. 

Hansenula polymorpha (methylamine oxidase) QI FT AANy E YC L YW V FMQDGAIR [46]... 

The most recent crystallographic study discloses the structure of the methylamine oxidase from the yeast Hansenula polymorpha [31], which shows an integrated network of water molecules providing electron transfer from topa quinone to copper and other important features such as the channel for oxygen entry and hydrogen peroxide release. The role of the active site aspartate base (Asp319) in the aminotransferase mechanism of the copper amine oxidase from H. polymorpha has been probed by site-directed mutagenesis [141]. It has been demonstrated by several... 

The natural ligand for the amine oxidase activity is not known for certain. While SSAO/VAP-1 will oxidize endogenous molecules such as methylamine and tyramine, the substrates associated with diapedesis are unknown. It has been speculated that leukocyte cell surface lysine residues or amino sugars, such as mannosamine residues (5) known to be associated with cell/cell recognition may be involved [14,15]. 

Lizcano, J.M., Unzeta, M. and Tipton, K.F. (2000) A spectrophotometric method for determining the oxidative deamination of methylamine by the amine oxidases. Analytical Biochemistry, 286, 75-79. 

METHYLAMINE DEHYDROGENASE AMINE OXIDASES AMINE SULFOTRANSFERASE Amino add acetyltransferase,... 

LYSYL OXIDASE METHANE MONOOXYGENASE METHIONINE y-LYASE METHYLAMINE DEHYDROGENASE... 

Vanillylamine [(4-hydroxy-3-methoxy-phenyl)methylamine] is the substrate of choice for the formation of vanillin with the help of amine oxidase. It can be obtained by cleavage of capsaicin (N-[(4-hydroxy-3-methoxy-phenyl)methyl]-8-methyl-6-nonenamide) isolated from pepper and capsicum [83]. As natural vanillin extracted from beans of Vanilla planifolia is rare and extremely expensive, this pathway for the production of natural vanillin is regarded to have a great potential. The vanillin obtained by the process can be labelled as natural if the cleavage of capsaicin is performed enzymatically. 

It has been shown that 3 is biotransformed in a reaction catalysed by monoamine oxidase B to species that cause the selective degeneration of nigrostriatal neurons, giving rise to a Parkinsonian syndrome in man and other primates. Studies of this process have shown that the pyridinium salts 4 and 5 are involved, and that 4 undergoes spontaneous disproportionation to 5 and 3 5 is the putative ultimate neurotoxin. More recent studies have shown that 4 undergoes a spontaneous reaction in pH 7.4 buffer to give methylamine and a product identified as 6. 

The excretion of amines is unusual in animals. Amines are highly toxic and one method employed by vertebrates to detoxify them is via monoamine oxidase, an enzyme which has been detected in H. diminuta (569). Amines can arise from the decarboxylation of the appropriate amino acid, e.g. glycine and alanine can give rise to methylamine and ethylamine, respectively. Another possible source of amines may be the reduction of azo or nitro compounds (39) and azo- and nitro-reductase activity has been reported from M. expansa (180, 181). Furthermore, the physiologically active amines octopamine, dopamine, adrenalin and serotonin (5-hydroxytryptamine) have been demonstrated in cestodes (283, 296, 435, 681, 682, 758, 859), where they probably function predominantly as neurotransmitters (see Chapter 2). 

No similar tryptophan docking motifs are present in the 7-bladed superbarrel proteins galactose oxidase and methylamine dehydrogenase, or in the 8-bladed nitrite reductase (cytochrome cJi) (Fulop et a/., 1995 Baker et al., 1997). 

Zhu, Z., and Davidson, V. L., 1998a, Methylamine dehydrogenase is a light-dependent oxidase, Biochim. Biophys. Acta 1364 2976300. 

Co = Catechol oxidase He = Hemocyanin Tyr = Tyrosinase MePy2 = Al,Al-bis(2-pyridylethyl)methylamine TACN = l,3,5-triazocyclononane TMPA = Tris[(2-pyridyl) methyljamine XYL-O = Q ,Q -bis[Al,Al-bis(2-pyridylethyl) amino]-m-xylene-2-olate XYL = Q ,Q -bis[A, Al-bis(2-pyri-dylethyl)amino]-m-xylene XYL-R = Meta substituted a,a -bis[Al,Al-bis(2-pyridylethyl)amtno]-m-xylene N3 = N,N, Al -Tetrakis-(2-pyridin-2-yl-ethyl)-propane-1,2-diamine N4 = Al,Al,Al, Al -Tetrakis-(2-pyridin-2-yl-ethyl)-butane-1,2-diamine N5 = Al,Al,Al, Al -Tetrakis-(2-pyridin-2-yl-... 

Three-dimensional structures. The TPQ-con-taining amine oxidase from E. coU is a dimer of 727-residue subunits with one molecule of TPQ at position 402 in each subunit. 7458 Methylamine dehydrogenase is also a large dimeric protein of two large 46.7-kDa subunits and two small 15.5-kDa subunits. Each large subunit contains a TTQ cofactor Reduced TTQ is reoxidized by the 12.5-kDa blue copper protein amicyanin. Crystal structures have been determined for complexes of methylamine dehydrogenase with amicyanin and of these two proteins with a third protein, a small bacterial cytochrome... 

A collection of redox enzymes for which efficient DET with electrodes has been observed is given in Table 2.3. Most of them are metaUoenzymes containing iron or copper. Many of these enzymes are part of electron transfer chains, i.e., have macromolecular redox partners, or react on large substrates. The evidence for DET has not always been presented by direct electrochemical measurements. In many cases the DET has been proved indirectly by measurement of a substrate dependent catalytic current. Various metabolites ranging from sugars such as fructose, cellobiose and gluconate [6], amines like methylamine and histamine [123], lactate [91],p-cresol [93] and drugs such as benzphetamine [74] can be measured with enzymes in direct contact to an electrode. The bioelectrocatalytic reaction of peroxide is one of the most important reactions not only for the determination of peroxide(s) in various media but also substrates of coupled oxidase [8] and enzyme inhibitors [130, 252]. Furthermore, enzyme immunoassays have been developed based on DET of peroxidase and laccase and electrodes [7,131,132]. 

Figure 4 Oxidation of a substituted methylamine by monoamine oxidase. R can be an alkyl (CHi) or aryl (CeHi) substituent.

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