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hemoglobin
Function:
- oxygen transport protein of erythrocytes
- hemoglobin can bind up to 4 O2 molecules
- oxygen-binding capacity of 1.34 mL of O2 per gram of hemoglobin; this increases the total blood oxygen capacity ~ 70 fold compared to dissolved oxygen in blood
- carries 10% of CO2 in blood bound to globin chain
- carries nitric oxide (NO) bound to globin thiol
- hemoglogin releases NO at the same time as O2
Structure:
- tetramer, generally heterotetramer of
- 2 hemoglobin alpha chains
- 2 hemoglobin beta chains
- hemoglobin Barts in an exception
- each chain is associated with 1 heme moeity
Compartment:
- cytoplasm
Expression:
- expressed in erythrocytes & erythroid precursors
- hemoglobin is also found in
- CNS
- dopaminergic neurons in the substantia nigra
- astrocytes in the cerebral cortex & hippocampus
- mature oligodendrocytes
- outside CNS
- macrophages
- alveolar cells
- mesangial cells in the kidney
Pathology:
- see hemoglobinopathy
Laboratory:
- hemoglobin in specimen
- hemoglobin in reticulocytes
- hemoglobin in body fluid
- hemoglobin in blood
- hemoglobin variant in blood
- hemoglobin subtype in blood
- hemoglobin in CSF
- hemoglobin.gastrointestinal in body fluid
- hemoglobin in pericardial fluid
- hemoglobin in peritoneal fluid
- hemoglobin in pleural fluid
- hemoglobin in synovial fluid
- free hemoglobin in serum/plasma
- hemoglobin in stool
- hemoglobin in urine
- hemoglobin electrophoresis
Related
heme
heme catabolism
heme synthesis
hemoglobin (Hgb) in blood
hemoglobin electrophoresis
hemoglobinopathy
mean corpuscular hemoglobin concentration (MCHC)
Specific
carboxyhemoglobin
deoxyhemoglobin
glycated hemoglobin
hemoglobin A
hemoglobin A2
hemoglobin F
hemoglobin Gower-1
hemoglobin Gower-2
hemoglobin Portland
hemoglobin-variant
methemoglobin (MetHb, Hi)
oxyhemoglobin
sulfhemoglobin
unstable hemoglobin
General
blood protein
heme protein
multisubunit protein
Properties
COMPARTMENT: cytoplasm
CELL: erythrocyte
SUBUNITS: hemoglobin alpha chain
:QUANTITY 2
hemoglobin beta chain
:QUANTITY 2
References
- Alperts et al Molecular Biology of the Cell, Garland
Publishing, New York, NY 1989 pg 289-291
- Wikipedia: Hemoglobin
http://en.wikipedia.org/wiki/Hemoglobin