Hemoglobin subunit alpha, Hemoglobin, alpha 1, is a

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

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

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

Gene

The human alpha globin

gene cluster A gene family is a set of homologous genes within one organism. A gene cluster is a group of two or more genes found within an organism's DNA that encode similar polypeptides, or proteins, which collectively share a generalized function and are o ...

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 globin ...

) 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., gene. ...

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 comprises about 97% of the total

; alpha chains combine with delta chains to constitute HbA-2, which with

fetal hemoglobin Fetal hemoglobin, or foetal haemoglobin (also hemoglobin F, HbF, or α2γ2) is the main oxygen carrier protein in the human fetus. Hemoglobin F is found in fetal red blood cells, and is involved in transporting oxygen from the mother's bloodstream ...

(HbF) makes up the remaining 3% of adult hemoglobin.

Clinical significance

Alpha

thalassemia Thalassemias are inherited blood disorders characterized by decreased hemoglobin production. Symptoms depend on the type and can vary from none to severe. Often there is mild to severe anemia (low red blood cells or hemoglobin). Anemia can result ...

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 - pseu ...

; some nondeletion alpha thalassemias have also been reported.

Interactions

Hemoglobin subunit alpha has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

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, hemoglobi ...

(HBB).

References

External links

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

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