Theoretical analysis of active transport through a reversed bienzyme porous membrane. II. Transport of an uncharged, small, hydrophilic molecule1Abbreviations used: Gro-3-P, glycerol-3-phosphate; GK, glycerolkinase; ATP, adenosine triphosphate; ADP, adenosine diphosphate; Pi, phosphate; PEP, phosphoenol pyruvate transferase system; USL, unstirred layer; SR, surconcentration ratio; PL, pollution level.1