Alpha chain

The term alpha chain is normally used to indicate one of the subunits of a multi-subunit protein. The term "chain" is a general term given to any peptide sequence. 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.