EC 2.4.1.139     
Accepted name: maltose synthase
Reaction: 2 α-D-glucose 1-phosphate + H2O = maltose + 2 phosphate
Systematic name: α-D-glucose-1-phosphate:α-D-glucose-1-phosphate 4-α-D-glucosyltransferase (dephosphorylating)
Comments: Neither free phosphate nor maltose 1-phosphate is an intermediate in the reaction.
References:
1.  Schilling, N. Characterization of maltose biosynthesis from α-D-glucose-1-phosphate in Spinacia oleracea L. Planta 154 (1982) 87–93. [PMID: 24275923]
[EC 2.4.1.139 created 1984]