Abstract: | Continuous-flow electrophoresis was used to separate pectin and coloured substances from extracts of lemon pectinesterase. Two minor lemon pectinesterases were subsequently separated from two major pectinesterases, using chromatography on Sephadex G-75 and CM-Sephadex C-50. One minor pectinesterase was stable at low pH, showed the same initial pectinesterase activity at 88°C as at 25°C, and was active at 85°C for 9 min. This enzyme destabilised the cloud of single-strength lemon juice. It is suggested that the minor pectinesterases might not be true isozymes, but could arise from association of a major enzyme with pectin. |