Molecular weight determination of membrane proteins by sedimentation equilibrium at the sucrose or Nycodenz-adjusted density of the hydrated detergent micelle11Dedication: In memory of our late friend Martin Zulauf, who crashed with his ‘Ultralight’ on June 17, 1995 in France. He published more than 50 papers on detergents and their interactions with proteins. It was always a pleasure to work with him and we hope that this modest contribution will be in his sense.