Hb S-Travis | beta6(A3)Glu->Val; |
---|---|
beta142(H20)Ala->Val |
HEMATOLOGY | Normal in the heterozygote | ||
ELECTROPHORESIS | Hb X moves to a position between Hb S and Hb F but closer to Hb S at alkaline pH; at acidic pH Hb X moves between Hb A and Hb S | ||
CHROMATOGRAPHY | Hb X and Hb A can be separated by DEAE-Sephadex chromatography; Hb X elutes immediately before Hb A | ||
STRUCTURE STUDIES | Tryptic digestion of the betaX chain; separation of peptides by cation exchange chromatography; amino acid analysis; sequencing | ||
DNA ANALYSES | Not reported; presumed mutation GAG->GTG and GCC->GTC at codons 6 and 142 | ||
FUNCTION STUDIES | Increased oxygen affinity; decreased affinity for 2,3-DPG and IHP; cooperativity and Bohr effect normal; sickling | ||
STABILITY | Tends to autooxidize; unstable | ||
OCCURRENCE | Found in members of a Black family in the USA | ||
OTHER INFORMATION | Quantity in the heterozygote ~14%; the mean gelling concentration of Hb X is similar to that of Hb S |
REFERENCES | |||
1. | Moo-Penn, W.F., Schmidt, R.M., Jue, D.L., Bechtel, K.C., Wright, J.M., Horne, M.K., Haycraft, G.L., Roth, E.F., and Nagel, R.L.: Eur. J. Biochem., 77:561, 1977. |