Mammalian alpha 1-antitrypsins: comparative biochemistry and genetics of the major plasma serpin.

1. Human alpha 1-antitrypsin (alpha 1 AT) has been extensively characterized and reviewed. It is the archetypal member of the superfamily of serine proteinase inhibitors, the serpins. As human alpha 1-antitrypsin exhibits a relatively high concentration in plasma and is usually the highest concentration serpin, it can be referred to as the major plasma serpin. 2. alpha 1-Antitrypsin from species other than man has been characterized for two major reasons: (1) for use in a model animal system to assist with the study of the human alpha 1 AT deficiency disease; and (2) to find polymorphism for use in gene mapping and linkage studies or for parentage analysis. 3. The diverse range of reasons for studying alpha 1AT has yielded a vast array of literature that is often not well cross-referenced. 4. The characteristic features of alpha 1AT in all species examined to date will be presented with a view to examining which features are important structurally and functionally from an evolutionary perspective. 5. In mouse, horse, rabbit and guinea pig, multigene families which appear to have arisen from alpha 1AT have been found. The functional and evolutionary implications of these paralogous genes will also be discussed.