The structure and function of serpins

4
The rerpinr are highly eifenive pmteaie inhibitm. tenaciously
gnpping their pmtcin target So ruccerrful is thc leipin mechanism
that an emodinanly diverie range of adaptations has
evolved. In some rerpinr inhibitoiy act~ily is anwaled by partimlii
ligands. In some ofthe rerpini' more disant mlatber.
inhtbtoiy artivly has been lost altogether and eherfunnronr
gained. II in the homone ciden thymxine- and cortiro.
stemid.binding globulini.
Serpinr aie partiwlady important in the conml ofpmteoiflic
carcadeder in the blood ansthmmbin inhibits blood clotting.
CI-inhibitor c~nmls mmplement anbation. and the inappmpnately
named SI -antitiypGn inhibits the elartare released by
inflammatoiy leukocltei. Abnomalitiei of plarma rerpini are
iurptisingiy common. and cause a vatiefy of direares - mainly of
the dmilation. Ai many as one in a loo0 people har an amnhmm.
bin abnomab, and ths a predspmiuon 10 thmmbosiit.
The best-studied abnormal sepini are ~ mam ofol-anti.
Wdn. Some IO per cent of Eumpeam rin is
wtheiized in homqgoter. it is ineiütiently secreted. Innead.