| haptoglobin | <protein> Acid _2 plasma glycoprotein that binds to oxyhaemoglobin that is free in the plasma and the complex is then removed in the liver. Tetrameric (2 _, 2 _ subunits): the existence of two different _ chains in humans means that haptoglobins can exist in three variants in heterozygotes. (18 Nov 1997) |
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| hemoglobin | <cell biology, haematology> Four subunit globular oxygen carrying protein of the erythrocytes of vertebrates and some invertebrates. It is a conjugated protein containing four haem groups and globin. There are two alpha and two beta chains (very similar to myoglobin) in adult humans, the haem moiety (an iron containing substituted porphyrin) is firmly held in a nonpolar crevice in each peptide chain. There are four globin polypeptide chains, designated alpha, beta, gamma, delta in the adult. Each is composed of several hundred amino acids. (08 Mar 2000) |