Lectins are carbohydrate-binding proteins that specifically recognize diverse sugar structures and mediate a variety of biological processes.Thus, it is important to elucidate the carbohydrate binding properties of a lectin including its thermodynamic binding parameters in order to understand its biological functions. The leguminous plants are recognized lectins fonts, which can be purified with different chromatography strategies. In this work , active fractions of a 2-N-acetilgalactosamine (2-NacGal) specific lectin isolated from Macrotyloma axillare seeds (LMA) are being studied by ITC and DSC methodologies. The lectin fractions were isolated from dormant and germinated M. axillare seeds by an alternative purification methodology (required patent at INPI, Brazil, 2004). A 29KDa double band was revealed in the 12,5% SDS-PAGE analysis. The thermal denaturation of the lectins fractions was monitored by a differential scanning microcalorimeter supplied by MicrocalÔ . The DSC experiments were accomplished at scanning speed of 60ºC/H and the system was maintained at constant pressure of 30.0 psi. The protein concentration used was 0.020-0.041mM. The isothermal titration experiments were carried out at 27ºC and pH 7.2 (NaCl 0.15M HEPES 20mM Buffer) with protein concentration of 0.16-0.27mM and 2-N-acetyl-galactosamine concentration (ligand) about 5-27mM. Preliminary ITC results shown that the LMA seed dormant fractions have dissociation constant about 2.6 mM and the DSC results shown that the LMA has Tm about 98°C. These results show that the LMA affinity by 2-NacGal is weak and its thermal stability at pH 7.2 is large. Other LMA lectin fractions purified from dormant and germinated seeds will be tested under these conditions by ITC and DSC and their thermodynamic parameters will be determined to obtain a complete LMA thermodynamic characterization.This work was supported by CNPq.