A comparison of the mechanism for the reductive half-reaction between pea seedling and other copper amine oxidases (CAOs).
In a previous DFT study a mechanism for the reductive half-reaction of pea seedling amine oxidase (PSAO) was suggested. In many of the suggested steps a lysine at the active site plays an important role. However, this lysine is not found in other amine oxidases. The primary aim of the present DFT study is therefore to investigate alternative mechanisms for those amine oxidases (CAO) where the lysine residue is not present. One of the most important roles suggested for the lysine in PSAO was to protonate the O2-site of TPQ before the critical Cbond;H bond cleavage of the substrate. In the absence of lysine the O2-site of TPQ is now suggested to be protonated by a water ligand on the copper metal complex, in line with experimental suggestions. In other steps the role of lysine is taken over by an asparagine. All results are compared with experimental observations and good agreement is generally found.
Prabhakar
Rajeev
R
Stockholm Centre for Physics, Astronomy and Biotechnology, Stockholm University, S-106 91 Stockholm, Sweden. raju@physto.se
Siegbahn
Per E M
PE
D006631:Amine Oxidase (Copper-Containing) / Q000737:chemistry* / Q000378:metabolism*; D001216:Asparagine / Q000378:metabolism; D001665:Binding Sites; D003300:Copper / Q000737:chemistry; D007700:Kinetics; D008239:Lysine / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry* / Q000378:metabolism*; D018532:Pisum sativum / Q000201:enzymology*; D012639:Seeds / Q000201:enzymology
D001216:Asparagine; D003300:Copper; D006631:Amine Oxidase (Copper-Containing); D000587:Oxidoreductases Acting on CH-NH Group Donors; D008239:Lysine