Amino acid substitutions in albumin variants found in Brazil.

Conventional horizontal starch-gel electrophoresis in four buffer systems and structural studies were performed on four albumin variants, and the findings were compared with similar previous data. Albumins Coari I and Porto Alegre I have a previously unreported amino acid substitution (glutamic acid replaced by lysine at position 358, denoted 358 Glu----Lys). The alteration in albumin Porto Alegre II (501 Glu----Lys) is the same as that found for three alloalbumins of Asiatic origin, designated Vancouver, Birmingham, and Adana. Albumin Oriximiná I has the same exchange as albumin Maku (541 Lys----Glu). Some of these findings can be explained only by the occurrence of independent mutations at the same site in the albumin gene. They also point to a third cluster of mutations in that gene, indicating hypermutability in some of its segments.