AMINO-ACID-SEQUENCE, BINDING-PROPERTIES AND EVOLUTIONARY RELATIONSHIPS OF THE BASIC LIVER FATTY-ACID-BINDING PROTEIN FROM THE CATFISH RHAMDIA-SAPO

The complete amino acid sequence of a basic liver fatty acid-binding p rotein (L-FABP) from catfish (Rhamdia sapo) was determined. Alignment of sequences shows that it has more similarity to chicken basic L-FABP than to mammalian L-FABP. The phylogenetic analysis suggests that bas ic L-FABP from catfish, thicken and iguana diverged from the mammalian protein before the fish-tetrapod divergence. thus implying that the t wo types are encoded by different penes. Supporting this conclusion, a 14-kDa protein: structurally closely related to mammalian L-FABP, was isolated from catfish intestine, indicating the presence of the two g enes in the same species. The catfish basic L-FABP binds only one fatt y acidi molecule, while mammalian L-FABP bind two, The former has more affinity for trans-parinaric acid than for cis-parinaric acid, in con strat to the latter proteins.