Diphosphoinositol polyphosphate phosphohydrolase NUDT4B (DIPP-2B) (EC 3.6.1.52) (Nucleoside diphosphate-linked moiety X motif 4B) (Nudix motif 4B) (Nudix hydrolase 4B)
1_MMKFK 6_ PNQTR 11_ TYDRE 16_ GFKKR 21_ AACLC 26_ FRSEQ 31_ EDEVL 36_ LVSSS 41_ RYPDQ 46_ WIVPG 51_ GGMEP 56_ EEEPG 61_ GAAVR 66_ EVYEE 71_ AGVKG 76_ KLGRL 81_ LGIFE 86_ QNQDR 91_ KHRTY 96_ VYVLT 101_ VTEIL 106_ EDWED 111_ SVNIG 116_ RKREW 121_ FKVED 126_ AIKVL 131_ QCHKP 136_ VHAEY 141_ LEKLK 146_ LGCSP 151_ ANGNS 156_ TVPSL 161_ PDNNA 166_ LFVTA 171_ AQTSG 176_LPSSV
1: Cleaves a beta-phosphate from the diphosphate groups in PP-InsP5 (diphosphoinositol pentakisphosphate), PP-InsP4 and [PP]2-InsP4 (bisdiphosphoinositol tetrakisphosphate), suggesting that it may play a role in signal transduction. Also able to catalyze the hydrolysis of dinucleoside oligophosphate Ap6A, but not Ap5A. The major reaction products are ADP and p4a from Ap6A. Also able to hydrolyze 5-phosphoribose 1-diphosphate. Does not play a role in U8 snoRNA decapping activity. Binds U8 snoRNA