Synthesizes trehalose from ADP-glucose and glucose. Has a much lower activity toward UDP-glucose and GDP-glucose. The reaction is reversible, the equilibrium strongly favors trehalose synthesis. an NDP-alpha-D-glucose + D-glucose = a ribonucleoside 5'-diphosphate + alpha,alpha-trehalose + H(+) Optimum pH is 6.5. Only 13% of activity is retained at pH 7.5. Optimum temperature is 90 degrees Celsius. 65% of activity remains at 100 degrees Celsius. Homodimer. By maltose, less efficiently by trehalose, and even less efficiently by sucrose. Belongs to the glycosyltransferase group 1 family. Glycosyltransferase 4 subfamily.