ADP-ribosyl protein lyase. Purification, properties, and identification of the product.
ADP-ribosyl protein lyase, formerly termed ADP-ribosyl histone-splitting enzyme (Okayama, H., Honda, M., and Hayaishi, O. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 2254-2257), was purified approximately 4,000-fold from rat liver and characterized. The purified enzyme exhibited a single protein band at the position of Mr = 83,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme split the bond between ADP-ribose and histone H2B or H1, and also acted on ADP-ribosyl pentapeptide (Pro-(ADP-ribosyl)Glu-Pro-Ala-Lys) of H2B but not its deadenylylated derivative, phosphoribosyl pentapeptide. The enzyme cleaved the bond between histone and mono(ADP-ribose), but hardly cleaved the bond with oligo- or poly(ADP-ribose). The enzymatic product was close to, but not identical with, ADP-ribose. The terminal ribose residue, obtained by hydrolysis of the split product by snake venom phosphodiesterase and alkaline phosphatase, was identified as 3-deoxy-D-glycero-pentos-2-ulose by the following gas chromatography-mass spectrometric analyses: 1) the reduced sugar was a mixture of 3-deoxy-threo- and 3-deoxy-erythro-pentitol, and 2) the deuterated reduced sugar was identical with that derived from synthetic 3-deoxy-D-glycero-pentos-2-ulose. This result indicated that the direct product was 5'-ADP-3"-deoxypent-2"-enofuranose, a dehydrated form of ADP-ribose, and that the enzyme is a lyase and not a hydrolase.