alpha chain

{{Short description|Subunit of a protein}}

{{distinguish|Alpha helix}}

{{more citations needed|date=August 2022}}

The term alpha chain is normally used to indicate one of the subunits of a multi-subunit protein.{{Cite book |last=Lesieur |first=Claire |url=https://books.google.com/books?id=vjehDwAAQBAJ&dq=%22protein+subunit%22+oligomer&pg=PA240 |title=Oligomerization of Chemical and Biological Compounds |date=2014-06-18 |publisher=BoD – Books on Demand |isbn=978-953-51-1617-2 |pages=240–241 |language=en}} The term "chain" is a general term given to any peptide sequence.{{Cite book |last=Weaver |first=Robert Franklin |url=https://www.worldcat.org/oclc/664665930 |title=Molecular biology |date=2012 |publisher=McGraw-Hill |isbn=978-0-07-352532-7 |edition=5th |location=New York |page=31 |oclc=664665930}} It can often refer more specifically to mean:

• a part of the T-cell receptor,
• the fibrinogen alpha chain,
• the integrin alpha chain,
• Hemoglobin, alpha 1

It should be distinguished from the term alpha helix, which refers to one of the common secondary structures found in proteins, along with beta sheet.