A complex of lanthanum perchloric acid coordinated with glutamic acid, La(Glu)(Im)(6)(ClO4)(3)center dot 4HClO(4)center dot 4H(2)O was synthesized and characterized. The biological effect of the complex was evaluated by microcalorimetry on the growth of E. coli DH5 alpha. Power-time curves of the growth metabolism of E. coil DH5 alpha were studied using a TAM Air Isothermal Microcalorimeter at 37 degrees C. From the power-time curves, the parameters such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (P-m) and the time of the maximum heat power (t(m)) were obtained. The results show that the concentrations of the complex affect obviously the growth metabolism of E. coli DH5 alpha. The stimulatory effect on growth of E. coil DH5a was observed when the concentration of the complex was kept in the range of (0-0.5 mu g mL(-1)). In contrast to the lower concentration, in the case of higher concentration of the complex (0.5-5.0 mu g mL(-1)), an inhibitory effect occurred. (C) 2010 Elsevier B.V. All rights reserved.