Open AccessFunctional Effects of the Coexistence of Hb-A with High Oxygen Affinity Hemoglobins
Author(s) -
G Ricco,
O David,
G Ivaldi,
Murray J. Girotti,
E. Rabino
Publication year - 2003
Publication title -
journal of biological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.218
H-Index - 6
eISSN - 2284-0230
pISSN - 1826-8838
DOI - 10.4081/jbr.2003.10560
Subject(s) - oxygen–haemoglobin dissociation curve , oxygen , p50 , chemistry , biochemistry , oxygenation , biophysics , hemoglobin , biology , microbiology and biotechnology , stereochemistry , gene , organic chemistry , ecology , transcription factor
In carriers of abnormal haemoglobins with increased oxygen affinity, polyglobulia is the only possible functional compensation for tissue hypoxia.However, this adaptation is reduced if some Hb-A is used to synthesize hybrid haemoglobins of the type a2bAbX (heterotetramers). In fact, they display increased oxygen affinity. Four patients of this kind were studied: two carriers of Hb-Kempsey: b 99Asp-Asn, one of Hb-Gàmbara: b 82Lys-Glu, and one of Hb- Trento, a new variant with elongated b chains. Moreover, there are some cases, like that of Hb- Tak, also with elongated b chains, and Hb-Casper: b 106Leu-Pro, in which the abnormal Hb does not interact with Hb-A to form hybrids and the patient presents good functional compensation. This is demonstrated by at least three signs: the absence of polyglobulia, the good reactivity of Hb-A towards 2,3-DPG, and the absence of left- shifting of the upper half of the dissociation curve,which is commonly considered the expression of Hb-A oxygenation.