This study was carried out to determine some of the biochemical properties of pectin methylesterase (PME) from black carrot. The enzyme showed very high activity in a broad pH range of 6.5-8.5, with the optimum pH occurring at 7.5. The optimum temperature for maximal PME activity was found to be 55 degrees C. NaCl enhanced PME activity, particularly at 0.2 M. K-m and V-max values for black carrot PME using apple pectin as substrate were found to be 2.14 mg/ml (r(2) = 0.988) and 3.75 units/ml, respectively. The enzyme was stable between the temperatures of 30-50 degrees C/5 min whereas it lost nearly all of its activity at 70 degrees C/5 min. E-a and Z values were found to be 196.8 kJmol(-1) (r(2) = 0.996) and 2.16 degrees C (r(2) = 0.995), respectively. (C) 2009 Elsevier Ltd. All rights reserved.