Densities (rho), sound velocities (u), and viscosities (eta) of glycine, DL-alpha-alanine, DL-alpha-amino-n-butyric acid, L-valine, and L-leucine, in aqueous solutions (0.1, 0.5, 1.0, and 1.5) mol . kg (1) of manganese chloride tetrahydrate, MnCl2 center dot 4H(2)O at different concentrations have been determined using a vibrating-tube digital densimeter, ultrasonic multifrequency interferometer and Ubbelohde type capillary viscometer attached with automatic viscosity measuring unit, respectively, within the temperature range (288.15 to 318.15) K. Partial molar volumes V-2 degrees, partial molar adiabatic compressibilities, K-S,K-2 degrees and viscosity B-coefficients have been determined from the above measurements. Further these data were used to calculate the corresponding transfer parameters (Delta V-t(2)degrees, Delta K-t(S,2)degrees and Delta B-t), hydration numbers, n(H), side chain group contributions, partial molar expansibilities, V-E degrees, dB/dT and related parameters. The data are discussed in terms of hydration of hydrophobic and hydrophilic parts of amino acids in these solutions. (C) 2011 Elsevier Ltd. All rights reserved.