Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong. limx54@yahoo.com|Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong. limx54@yahoo.com|Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong. limx54@yahoo.com|Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong. limx54@yahoo.com|Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong. limx54@yahoo.com