In enzymology, a cellobiose phosphorylase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are cellobiose and phosphate, whereas its two products are alpha-D-glucose 1-phosphate and D-glucose.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is cellobiose:phosphate alpha-D-glucosyltransferase. This enzyme participates in starch and sucrose metabolism.
As of late 2006, two structures have been solved for this class of enzymes, with PDB accession codes and .