Lentil seedling amine oxidase

It will be seen from Figure 13 that copper is not invoked for the catalytic steps of the reductive half cycle and an unresolved issue is whether the copper-free form of amine oxidase can catalyse the reactions leading to the aminoquinol form of the TPQ cofactor and release of product aldehyde. For the lentil seedling amine oxidase (Rinaldi et al., 1989), it has been reported that the copper-free form can catalyse the reactions of the reductive half cycle but that the presence of copper is required for the TPQ semiquinone species to be observed (Bellelli et al., 1985). Further work is needed to establish fully the catalytic properties of apo-forms and metal substi-tuted-forms of amine oxidases. 

Rinaldi, A., Giartosio, A., Eloris, G., Medda, R., and Einazzi-Agro, A., 1989, Lentil seedling amine oxidase preparation and properties of the copper-free enzyme, Biochem. Biophys. Res. Commun., 120 242n249. 

Bellelli, A., Brunori, M., Finazzi-Agro, A., Floris, G., Giartosi, A., and Rinaldi, A., 1985, Transient kinetics of copper-containing lentil Lens culinari) seedling amine oxidase, Biochem. J. 232 9239926. 

Recently, the cofactor peptides have also been isolated from semicarbazide-sensitive amine oxidases purified from bovine and porcine aortas [52], sequenced and confirmed to contain the topa quinone. The same topa quinone consensus sequence was also found in the primary structures of amine oxidases from human kidney [53], human retina [54] and rat colon [55], so called amiloride-binding proteins , and amine oxidase from human placenta [56] that shows 81% identity with bovine plasma amine oxidase [57], bovine lung amine oxidase [58], and amine oxidases from pea and lentil seedlings [59,60], chick pea seedlings [61], and Arabidopsis thaliana [62] obtained by the molecular cloning of respective DNAs. 

The effect of Cu(II) ions on amine oxidase production in lentil seedlings has been described previously [155]. While the amount of specific mRNA and the protein was not affected by exogenous addition of Cu(II), addition of cupric ions to the homogenized seedlings grown in its absence led to an essential increase in the enzymatic activity. On the other hand, the addition of copper into cultivating media increased the enzyme expression in the case of monoamine oxidase of E. coli [156]. Several 4-... 

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