Late protein which probably participates in disulfide bond formation by functioning as a thiol-disulfide transfer between membrane-associated E10 and G4. The complete pathway for formation of disulfide bonds in intracellular virion membrane proteins sequentially involves oxidation of E10, A2.5 and G4 (By similarity). Interacts with sulfhydryl oxidase E10; this interaction involves formation of a transient disulfide-bonded intermediate, allowing disulfide bond transfer. Interacts with G4; this interaction involves formation of a transient disulfide-bonded intermediate, allowing disulfide bond transfer (By similarity). Expressed in the late phase of the viral replicative cycle. Belongs to the chordopoxvirinae A2.5 family.