Human Factor IXa-beta
Human Factor IXa is prepared from Human Factor IX by activation with Bovine Factor XIa. This Bovine Factor XIa is removed after activation. Complete activation is observed by SDS-PAGE. The Factor XIa activates Factor IX in a two-step reaction. In the first step, an internal Arg-Ala bond is cleaved, and in the second step, an Arg-Val bond is cleaved. The second cleavage leads to the liberation of an activation peptide from the NH2-terminal portion of the heavy chain to produce Factor IXa-beta. Factor IXa-alpha has only the second cleavage at the Arg-Val bond with about half the coagulant activity of Human Factor IXa-beta. Complete activation is observed by SDS-PAGE. This protein purity is determined by SDS-PAGE and shows total reduction upon incubation with 2-mercaptoethanol. Thaw rapidly in a 37C water bath without allowing protein to warm to 37C and immediately cool on ice.