cDNA-derived amino-acid sequence of lentil seedlings' amine oxidase

Abstract

Lentil seedlings' amine oxidase (LSAO) cDNAs were identified in a cDNA lambda gt 10 library by plaques hybridization. The nucleotide sequence of a 2111 bp clone was determined. It contains part of a signal peptide, the complete sequence coding for the mature protein and the 3'-untranslated region of the mRNA. The deduced protein sequence shows that the mature protein is composed of 569 amino acids with a molecular mass of 67 kDa, also taking into account the glucidic component. The LSAO cDNA was identified by sequencing the N-terminal part of the protein and several tryptic peptides. The protein sequence shows a characteristic hexapeptide present in amine oxidases containing 6-hydroxydopa as the organic cofactor. Three conserved histidines might be the ligands of copper bound to the enzyme.