Hemoglobin subunit alpha, Hemoglobin, alpha 1, is a

hemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''HBA1''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Gene

The human alpha globin

gene cluster A gene cluster is a group of two or more genes found within an organism's DNA that encode similar peptide, polypeptides or proteins which collectively share a generalized function and are often located within a few thousand base pairs of each othe ...

located on chromosome 16 spans about 30 kb and includes seven loci: 5'- zeta - pseudozeta - mu - pseudoalpha-1 - alpha-2 - alpha-1 - theta - 3'. The alpha-2 (

HBA2 Hemoglobin, alpha 2 also known as ''HBA2'' is a gene that in humans codes for the alpha globin chain of hemoglobin. Function The human alpha globin gene cluster is located on chromosome 16 and spans about 30 kb, including seven alpha like glo ...

) and alpha-1 (HBA1; this gene) coding sequences are identical. These genes differ slightly over the 5' untranslated regions and the

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e., a region inside a gene."The notion of the cistron .e., gen ...

s, but they differ significantly over the 3' untranslated regions.

Protein

Two alpha chains plus two beta chains constitute HbA, which in normal adult life accounts for about 97% of the total

; alpha chains combine with delta chains to constitute HbA-2, which with fetal hemoglobin (HbF), composed of alpha and gamma chains, make up the remaining 3% of adult hemoglobin.

Clinical significance

Alpha

thalassemia Thalassemias are a group of Genetic disorder, inherited blood disorders that manifest as the production of reduced hemoglobin. Symptoms depend on the type of thalassemia and can vary from none to severe, including death. Often there is mild to ...

s result from deletions of each of the alpha genes as well as deletions of both

and

HBA1 Hemoglobin subunit alpha, Hemoglobin, alpha 1, is a hemoglobin protein that in humans is encoded by the ''HBA1'' gene. Gene The human alpha globin gene cluster located on chromosome 16 spans about 30 kb and includes seven loci: 5'- zeta - pse ...

; some nondeletion alpha thalassemias have also been reported.

Interactions

Hemoglobin subunit alpha has been shown to interact with

hemoglobin subunit beta Hemoglobin subunit beta (beta globin, β-globin, haemoglobin beta, hemoglobin beta) is a globin protein, coded for by the ''HBB'' gene, which along with alpha globin ( HBA), makes up the most common form of haemoglobin in adult humans, hemoglo ...

(HBB).

References

External links

GeneReviews/NCBI/NIH/UW entry on Alpha-Thalassemia

OMIM entries on Alpha-Thalassemia
* Hemoglobins {{DEFAULTSORT:Hemoglobin, alpha 1