ID 2.7.1.156 DE adenosylcobinamide kinase. AN adenosylcobinamide kinase/adenosylcobinamide-phosphate AN guanylyltransferase. AN AdoCbi kinase/AdoCbi-phosphate guanylyltransferase. CA (1) adenosylcob(III)inamide + GTP = adenosylcob(III)inamide phosphate + CA GDP + H(+). CA (2) adenosylcob(III)inamide + ATP = adenosylcob(III)inamide phosphate + CA ADP + H(+). CC -!- In Salmonella typhimurium LT2, under anaerobic conditions, CobU CC (EC 2.7.7.62 and EC 2.7.1.156), CobT (EC 2.4.2.21), CC CobC (EC 3.1.3.73) and CobS (EC 2.7.8.26) catalyze reactions in the CC nucleotide loop assembly pathway, which convert adenosylcobinamide CC (AdoCbi) into adenosylcobalamin (AdoCbl). CC -!- CobT and CobC are involved in 5,6-dimethylbenzimidazole activation CC whereby 5,6-dimethylbenzimidazole is converted to its riboside, CC alpha-ribazole. CC -!- The second branch of the nucleotide loop assembly pathway is the CC cobinamide (Cbi) activation branch where AdoCbi or CC adenosylcobinamide-phosphate is converted to the activated CC intermediate AdoCbi-GDP by CobU. CC -!- The final step in adenosylcobalamin biosynthesis is the condensation CC of AdoCbi-GDP with alpha-ribazole, which is catalyzed by CobS CC (EC 2.7.8.26), to yield adenosylcobalamin. CC -!- CobU is a bifunctional enzyme that has both kinase (EC 2.7.1.156) and CC guanylyltransferase (EC 2.7.7.62) activities. CC -!- However, both activities are not required at all times. CC -!- The kinase activity has been proposed to function only when CC S.typhimurium is assimilating cobinamide whereas the CC guanylyltransferase activity is required for both assimilation of CC exogenous cobinamide and for de novo synthesis of adenosylcobalamin. DR Q9I466, COBP_PSEAE ; P29931, COBP_SINSX ; P0AE77, COBU_ECO57 ; DR P0AE76, COBU_ECOLI ; Q05599, COBU_SALTY ; //