JMSSJ On-line

JMSSJ On-line, Vol. 48 (2000) No. 5, pp. 341-345

Hemoglobin Tokyo II [α89 (FG1) His→Asn]: A New Hemoglobin Variant Characterized by Endoproteinase Asp-N Digestion and Collision-Induced Dissociation		>> Full Text PDF >> References
*Tomokazu NAKANO^a) and Yoshinao WADA^a)** ^† This paper is dedicated to the memory of the late Professor Takekiyo MATSUO. ^a) Department of Molecular Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health (840 Murodo-cho, Izumi, Osaka 594-1101, Japan)*

The presence of a hemoglobin mutant was suggested in a male subject who showed an apparently false level of glycated hemoglobin based on ion-exchange chromatography. Electrospray ionization mass spectrometry detected a mutant molecule with a mass of 15, 103 units, 23 units less than normal α-globin. The mutation was identified in a large tryptic peptide, αT9, of residues 62-90. Endoproteinase Asp-N digestion of carboxymethylated α-globin cleaved the region into peptides of ca. 1,000 Da, and localized the mutation to the peptide corresponding to residues 85-94. Collision-induced dissociation of the mutated peptide identified an amino acid substitution, Hisrarr;Asn, at position 89. This is a newly described mutation and the mutant was named Hb Tokyo II.

Key words: Hemoglobin, Mutation, CID, MS/MS