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The variant fetal hemoglobin F Texas I is abnormally acetylated
Author(s) -
Keitt Alan S.,
Jones Richard T.
Publication year - 1988
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830280110
Subject(s) - edman degradation , isoelectric focusing , chemistry , fetal hemoglobin , hemoglobin , chromatography , high performance liquid chromatography , acetylation , peptide , fast atom bombardment , fetus , mass spectrometry , biochemistry , peptide sequence , enzyme , biology , pregnancy , genetics , gene
Abstract Two related infants with indistinct slow‐moving minor hemoglobin bands were detected by electrophoretic cord blood screening. The variant separated into a major and a minor band on isoelectric focusing (IEF), anion exchange chromatography (AEC), and high‐performance liquid chromatography (HPLC). Analysis of the products of tryptic hydrolysis of the abnormal chain revealed a truncated AγT‐l peptide containing a glu→lys substitution at position 5, identifying the variant as Hb F Texas 1. Microsequencing of the major early peak from AEC confirmed the substitution. However, γ chains from the minor peak resisted Edman degradation and were shown to be acetylated by fast atom bombardment mass spectrometry (FABMS). Acetylation of HbF Texas I was nearly three times that of normal HbF measured in the same hemolysate, and this ratio remained constant for over 1 year in the proband. This represents the first demonstration of increased Nα‐acetylation of a variant fetal hemoglobin.