Sequence determination and analysis of S-adenosyl-L-homocysteine hydrolasefrom yellow lupine (Lupinus luteus)

The coding sequences of two S-adenosyl-L-homocysteine hydrolases (SAHases) were identified in yellow lupine by screenig of a cDNA library. One of them , corresponding to the complete protein, was sequenced and compared with 52 other SAHase sequences. Phylogenetic analysis of these proteins identified three groups of the enzymes. Group A comprises only bacterial sequences. G roup B is subdivided into two subgroups, one of which (B1) is formed by ani mal sequences. Subgroup B2 consist of two distinct dusters, B2a and B2b. Cl uster B2b comprises all known plant sequences, including the yellow lupine enzyme, which are distinguished by a 50-residue insert. Group C is heteroge neous and contains SAHases from Archaea as well as a new class of animal en zymes, distinctly different from those in group B1.