Extraction and characterisation of pectin methylesterase from black carrot (Daucus carota L.)

摘要

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 ℃. 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 ℃/5 min whereas it lost nearly all of its activity at 70℃/5 min. E_a and Z values were found to be 196.8 kJmol~(-1) (r~2 = 0.996) and 2.16 ℃ (r~2 = 0.995), respectively.