Alpha78(EF7)Asn-->Asp is a posttranslational modification in Hb J-Singapore [alpha78(EF7)Asn-->Asp;alpha79(EF8)Ala-->Gly].
In Hb J-Singapore, the alpha78(EF7)Asn-->Asp and alpha79(EF8)Ala-->Gly substitutions were initially thought to be genetic mutations. Subsequent studies on other similar hemoglobin variants suggested that the Asn-->Asp change was a posttranslational modification. Nevertheless, lack of DNA evidence made it difficult to confirm the deamidation in Hb J-Singapore. We recently encountered a female patient with Hb J-Singapore trait. In this report, we present electrospray mass spectrometry and DNA data to confirm the alpha78(EF7)Asn-->Asp is indeed a posttranslational modification.
O'Brien
David A
DA
Department of Haematology, St James's Hospital, Dublin, Ireland.
Clark
Barnaby
B
Rai
Dilip K
DK
D000328:Adult; D005260:Female; D006448:Hemoglobin J / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D011499:Protein Processing, Post-Translational; D021241:Spectrometry, Mass, Electrospray Ionization
D006448:Hemoglobin J