1. Carlsberg Research Laboratory (A.D.),
2. Department of Physiology (K.K.T., D.J.S.), and
3. Department of Biophysics, Escola Paulista de Medicina, Rua Tres de Maio 100, Sao Paulo 04044–020, Brazil (M.A.J., L.C.A.).
4. Department of Chemistry (I.S.), Carlsberg Laboratory, Gamle Carlsbergvej 10, DK–2500 Valby, Denmark; and