title: Hemoglobin Louisville (beta-42 (CD1) phe-leu): an unstable variant causing mild hemolytic anemia.
abstract: An unstable hemoglobin variant termed Hb Louisville, was found in four members of a Caucasian family, who were suffering from a mild hemolytic anemia. The variant showed a decreased stability upon warming at 65 degrees C and an increased tendency to dissociate in the presence of sulfhydryl group-blocking agents. The structural abnormality was identified as a replacement of phenylalanyl residue in position 42 (CD1) by a leucyl residue. Substitution of this phenylalanyl residue, which participates in the contact with heme, by a nonpolar leucyl residue has apparently less severe consequences than a replacement of the same residue by a polar seryl residue as in Hb Hammersmith. Oxygen equilibrium studies of total hemolysate from one Hb Louisville heterozygote indicated a decreased oxygen affinity, a marked decrease in heme-heme interaction, and a normal Bohr effect. Studies with isolated Hb Louisville were not made because it was not possible to separate the variant from normal Hb A.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000743:Anemia, Hemolytic / Q000097:blood*; D002729:Chloromercuribenzoates; D002852:Chromatography, Ion Exchange; D004906:Erythrocyte Count; D006366:Heinz Bodies; D006400:Hematocrit; D006455:Hemoglobins, Abnormal / Q000032:analysis*; D006801:Humans; D006827:Hydantoins; D006902:Hydroxymercuribenzoates; D010100:Oxygen / Q000097:blood; D010375:Pedigree; D010455:Peptides / Q000032:analysis; D013053:Spectrophotometry
chemical_list: D000596:Amino Acids; D002729:Chloromercuribenzoates; D006455:Hemoglobins, Abnormal; D006827:Hydantoins; D006902:Hydroxymercuribenzoates; D010455:Peptides; D010100:Oxygen