title: Adenovirus type 2 endopeptidase: an unusual phosphoprotein enzyme matured by autocatalysis.
abstract: A 19-kDa protein, present in low copy number in purified adenovirus type 2, has been characterized. Several criteria were used to establish that this protein is neither a degradation product of the known structural proteins of the virion nor a minor, unusually modified, form of protein VII. This 19-kDa protein, unlike other virion proteins, possesses alkali-resistant phosphoamino acids. Analysis by partial proteolysis indicated that it is related to a 23-kDa phosphoprotein present in H2ts-1 virions assembled in infected cells maintained at 39 degrees C. Affinity labeling with [3H]diisopropyl fluorophosphate showed that the 19-kDa protein contains the active site for a serine protease. We, therefore, conclude that the 19-kDa protein is the active form of the adenovirus-encoded endopeptidase, defined by the H2ts-1 mutation, and is synthesized as a 23-kDa precursor that appears to mature by autocatalysis.
mesh_terms: D000260:Adenoviruses, Human / Q000201:enzymology* / Q000502:physiology; D000596:Amino Acids / Q000032:analysis; D010450:Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D008970:Molecular Weight; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D014771:Virion / Q000201:enzymology / Q000502:physiology
chemical_list: D000596:Amino Acids; D010750:Phosphoproteins; D010450:Endopeptidases