Identification of a 27.5 kDa, thiol-independent arginine-specific adenosine diphosphate (ADP)-ribosyltransferase in chicken bone marrow cells

Though two arginine-specific adenosine diphosphate (ADP)-ribosyltransferase cDNAs AT1 and AT2 were cloned from chicken bone marrow cell cDNA library, the transferase corresponding to native AT2 has not been detected. In the present study, we examined whether the native AT2 transferase is present in chicken bone marrow cells. An arginine-specific ADP-ribosyltransferase (AT-H) was separated from the bone marrow cell extract by gel filtration chromatography. AT-H and recombinant AT2, sharing the common chromatographic properties, were thiolindependent and activated by salts while native AT1 required thiol reagents for its activity and was inhibited by salts. These results suggest that the newly detected ADP-ribosyltransferase AT-H is probably the native AT2 transferase.