Serpins - More than protease inhibitors

As I have noted/complained/trumpeted in past posting on this site, I am working on a book entitled "Biotechnology of the Plasma Proteins." And, I don't mind saying that it has turned out to be a bit more complicated than I expected such that I pleaded for a six month extension and that might not be enough. I am currently working on a chapter on Proteinase inhibitors in Plasma - all serpins except for alpha-2-macroglobulin. I expected alpha-2-macroglobulin to be complex and some elegant work from a place 10 miles from my humble abode; Sal Pizzo's laboratory at Duke University where he and his colleagues have shown a major role for alpha-2-macroglobulin in prostate cancer (Misra U.K., Payne, S., and Pizzo, S.V., Ligation of prostate cancer cell surface GRP78 activates a proproliferative and antiapoptotic feedback loop. A role for secreted prostate-specific antigen, J.Biol.Chem. 286, 1248-1259, 2011). However, I have been really surprised by the complexity of antithrombin and alpha-1-antitrypsin. Antitrypsin has a free sulfhydryl group of unknown function which had somehow escaped my attention and antithrombin appears to be anti-angiogenic (See previous post). At least, there has been a modest amount of work on the cysteine residue in antitrypsin; little if anything on alpha-2-antiplasmin which is currently on the table.

Update to follow - any thoughts appreciated at