Calcium-responsive mitochondrial glycerol-3-phosphate dehydrogenase which seems to be a key component of the pancreatic beta-cell glucose-sensing device. a quinone + sn-glycerol 3-phosphate = a quinol + dihydroxyacetone phosphate Calcium-binding enhance the activity of the enzyme. Polyol metabolism; glycerol degradation via glycerol kinase pathway; glycerone phosphate from sn-glycerol 3-phosphate (anaerobic route): step 1/1. Belongs to the FAD-dependent glycerol-3-phosphate dehydrogenase family.