Structure and variation of human alpha 1-antitrypsin.

The sequence of alpha 1-antitrypsin is in keeping with its role as a tissue scavenger of leukocyte elastase. Two abnormal variants commonly present in Europeans cause a deficiency that predisposes them to a progressive loss of lung elasticity. The nature of the reactive centre helps explain why cigarette smoking greatly accelerates the onset and severity of this degenerative process to give the disease emphysema.