Has both ADP-ribosyltransferase activity and thiol-dependent NAD(+) glycohydrolase activity. L-arginyl-[protein] + NAD(+) = H(+) + N(omega)-(ADP-D-ribosyl)-L-arginyl-[protein] + nicotinamide H2O + NAD(+) = ADP-D-ribose + H(+) + nicotinamide Expressed in spleen, intestine and thymus. In intestine, the expression levels are highest during neonatal stages and decrease towards adulthood. In spleen, the expression is lowest in neonatals and increases during further developmental stages. It is proposed that in the absence of reducing agents, a disulfide bond is formed between Cys-80 and Cys-201, leading to a conformational change that reduces the catalytic rate of NAD glycohydrolysis. A subset of Rt6+ regulatory T-cells may confer protection to autoimmune disease, and failure to develop this subset may result in enhanced susceptibility for autoimmune disease. Belongs to the Arg-specific ADP-ribosyltransferase family. Defined as a polymorphic pseudogene by MGI. In strain C57BL/6, a polymorphism creates a premature stop codon at position 161. PubMed:9300695 shows that the truncated protein is not functional.