Bovine aorta amine oxidase

Unlike bovine serum amine oxidase, which is available in gram quantities and was used as the prototypic system for the establishment of TPQ, a typical preparation of LO yields about 5 mg (starting with about 500 grams of aorta tissue). In an effort to minimize protein loss, purification was stopped after the stage where LO (32 kDa) coelutes with a second protein (24 kDa) from Sephacryl S-200 gel filtration. The two-banded protein was labeled with [ 4C]phenyl-hydrazine, to yield the expected chromophore for a phenylhydrazone derivative of a quinone structure (Fig. 1). Analysis of the i C-labeled protein by SDS gel electrophoresis showed almost exclusive incoiporation of into the 32-kDa LO band (13). Therefore, the unreactive 24-kDa band would not affect subsequent procedures since selection of active site-derived peptides from LO was dependent on screening for in addition to monitoring die UV-Vis absorption of the newly formed chromophore. 

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. 

An amino oxidase that catalyzes the oxidation of peptidyllysine to form a-aminoadipic-6-semialdehyde (allysine) has been isolated from bovine aorta (Rucker et al., 1970) and chick aorta (Harris et al, 1974). This enzyme has been given the name lysyl oxidase to differentiate it from other amine oxidases. Lysyl oxidase contains copper and apparently requires pyridoxal phosphate as a cofactor (Chou et al., 1970). 

B. L, (1970) Oxidation of peptidyl lysine by an amine oxidase from bovine aorta. Biochem. Biophys. Res. Commun, 40 1391. 

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