Comparative studies on the partial purification and characterization of rhodanese from seed and mesocarp of snake tomatoes (Trichosanthes cucumerina Linn.)

Rhodanese enzyme was partially purified and characterized from seed and mesocarp of snake tomato (Trichosanthes cucumerina) using 80% ammonium sulphate precipitation. The enzyme isolated from T. cucumerina mesocarp had a specific activity of 8.8 RU/mg with a percentage yield of 87.8%, while that from T. cucumerina seed had a specific activity of 19.7 RU/mg with a percentage yield of 14.6%. The Km of rhodanese from T. cucumerina mesocarp and seed for sodium thiosulphate (Na2S2O3) and potassium cyanide (KCN) were 12.5 and 10 mM, respectively. The enzyme from both mesocarp and seed was not inhibited by ammonium persulphate and sodium metabisulphite. The optimum temperature for both the seed and the mesocarp rhodanese was 50°C, while the optimum pH was 8.0 and 7.0, respectively. Rhodanese from T. cucumerina mesocarp was not inhibited by the metal ions at concentrations of 0.01 and 0.001 M, while rhodanese from the seed was inhibited by the metal ions at the two concentrations of each of the salts (KCl, MnCl2, NaCl, NiCl2, ZnCl2 and BaCl2).   Key words: Rhodanese, Trichosanthes cucumerina, seed, mesocarp.