Abstract: Objectives To characterize some purified recombinant Apo(a) kringles expressed by Pichia pastoris and to illustrate their antiangiogenic and antitumorogenic capacities. Methods Two recombinant proteins RHAKA (kringle V) and RHAKB (kringle IV type 10 and kringle V) were expressed by Pichia pastoris. Both RHAKA and RHAKB, recombined into pPICZ?A, were secreted by Pichia pastoris X-33. Recombinant proteins were concentrated and dialyzed before His?Tag affinity chromatography. Six amido terminal amino acids of RHAKB were analyzed through sequencing the purified protein from reverse-phase high performance liquid chromatography. We’ve also illustrated several important characters of recombinant proteins, such as glycosylation and disulfide bonds formation. Finally, recombinant proteins’ influence on in vitro cellular proliferation and in vivo angiogenesis of chick embryo chorioallantoic membrane (CAM) were tested. Results We observed that Pichia pastoris as an expression host could not only express recombinant proteins at a high level but modify them well. Both RHAKA and RHAKB could inhibit angiogenesis in vitro or in vivo, but no such inhibitory effect on cultured carcinoma cells. Conclusion Recombinant Apo(a) carboxyl terminal kringles expressed by Pichia pastoris could inhibit angiogenesis significantly.

Key words: apolipoprotein(a), kringle, Pichia pastoris, angiogenesis