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.

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This material is from the book A Syllabus of Human Hemoglobin Variants (1996) by Titus H.J. Huisman, Marianne F.H. Carver, and Georgi D. Efremov, published by The Sickle Cell Anemia Foundation in Augusta, GA, USA. Copyright © 1996 by Titus H.J. Huisman. All rights reserved. Neither this work nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, microfilming and recording, or by any information storage and retrieval systems, without written permission.