A novel compound comprising an immunologically invisible polyethylene glycol copolymer is used to carry one or more immunologically reactive substances. A power MOSFET of the present invention has a semiconductor material which is disposed under a polysilicon gate and composed of polysilicon into which impurities are doped at low concentration. A portion of the first insulating pattern is etched by self-aligned contact etching to form a first contact hole. The distal end of the mandrel is insertable into the lumen of the vessel. Trehalose can be manufactured advantageously in an industry scale from D-glucose and -D-glucose 1-phosphoric acid using this enzyme.