Adenosylcobinamide phosphate guanylyltransferase

In enzymology, an adenosylcobinamide-phosphate guanylyltransferase (EC 2.7.7.62) is an enzyme that catalyzes the chemical reaction

GTP + adenosylcobinamide phosphate ⇌ diphosphate + adenosylcobinamide-GDP

Thus, the two substrates of this enzyme are GTP and adenosylcobinamide phosphate, whereas its two products are diphosphate and adenosylcobinamide-GDP.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). The systematic name of this enzyme class is GTP:adenosylcobinamide-phosphate guanylyltransferase. Other names in common use include CobU, adenosylcobinamide kinase/adenosylcobinamide-phosphate, guanylyltransferase, and AdoCbi kinase/AdoCbi-phosphate guanylyltransferase. This enzyme participates in porphyrin and chlorophyll metabolism.