Gamma chains make up the fetal hemoglobin F, in combination with alpha chains. Hemoglobin subunit gamma-1/HBG1 Protein, Human, Recombinant (His & Myc) is expressed in E. coli expression system with N-10xHis and C-Myc tag. The predicted molecular weight is 23.0 kDa and the accession number is P69891.

Hemoglobin subunit alpha 1 (HBA1), also known as α2β2, is a hetero-tetramer consisting of two α and two β subunits held together by non-covalent interactions. Each subunit contains a heme group with an iron atom in the Fe2+ state. Cooperativity of Hemoglobin (Hb) in binding with O2 and allosteric regulatory binding properties with CO2, H+, Cl−, and 2,3-DPG (2,3-bisphosphoglycerate) are based on subunit interactions. HBA1 is the most common type of Hb in adult humans, which mediates the transport of oxygen and carbon dioxide in the blood. In recent years, Hb α and β chains have been found co-expressed in alveolar cells, mesangial cells of the kidney, retinal ganglion cells, hepatocytes and neurons. Endothelial and peripheral catecholaminergic cells express exclusively the α chain, while macrophages present the β chain only.

Hemoglobin subunit theta-1 is a protein that in humans is encoded by the HBQ1 gene. Theta-globin mRNA is originally found in human fetal erythroid tissue but not in adult erythroid or other nonerythroid tissue. Theta-1 is a member of the human alpha-globin gene cluster that includes five functional genes and two pseudogenes. Research supports a transcriptionally active role for the gene and a functional role for the peptide in specific cells, possibly those of early erythroid tissue. Hemoglobin has a quaternary structure characteristically composed of many multi-subunit globular proteins. Most of the amino acids in hemoglobin form alpha helices, connected by short non-helical segments. Hydrogen bonds stabilize the helical sections inside this protein, causing attractions within the molecule, folding each polypeptide chain into a specific shape. Hemoglobin's quaternary structure comes from its four subunits in roughly a tetrahedral arrangement.

Hemoglobin Subunit Zeta (HBZ) is a member of the Globin family. The zeta chain is an alpha-type chain of mammalian embryonic Hemoglobin that is synthesized primarily in the yolk sac of the early embryo, while alpha-globin is produced throughout fetal growth and adult life. The HBZ gene consists of five functional genes and two pseudogenes, the order of genes is 5-zeta-pseudozeta-mu-pseudoalpha-1-alpha-2-alpha-1-theta-1-3.