The Collaborative International Dictionary
globin \globin\ n. (Biochem.) a colorless protein obtained by removing heme from hemoglobin; the protein part of hemoglobin.
n. (context protein English) One of several polypeptides that are the protein components of haemoglobin in blood.
The globins are a family of globular proteins, which are thought to share a common ancestor. These proteins all incorporate the globin fold, a series of eight alpha helical segments. Two prominent members of this family include myoglobin and hemoglobin, which both bind the heme (also haem) prosthetic group. Both of these proteins are reversible oxygen binders.
Usage examples of "globin".
The globin component consists of four polypeptide chains, which are designated alpha, beta, gamma, and so forth, according to their amino-acid makeup.
This charge caused one end of a globin molecule to bind with the end of the other.
Yet the eight globins, descendants as they are of these remote branchings in distant ancestors, are still all present inside every one of us.
About 1,100 million years ago, the ancestral globin gene duplicated, forming two genes.
Various subsequent duplications have given rise to the so-called alpha, beta, gamma, delta, epsilon and zeta globins.
The fascinating thing is that we can construct a complete family tree of all the globin genes, and even put dates on all the divergence points (delta and beta globin parted company, for example, about 40 million years ago, epsilon and gamma globins 100 million years ago).
We can date this event because of independent evidence about how fast globins habitually evolve (see Chapters 5 and 11).