Identification of Enzymatic Properties in Crocus sativus Roots

Even though saffron is the most expensive spice in the world, knowledge on the biology of the producing plant (Crocus sativus L.) is still limited. In this research we report the identification and kinetics properties of some enzymes active in the plant’s roots. Dormant corms planted in potted soil were collected after 20 days. The roots had grown at an average rate of 3.8 mm/day for the first ten days and of 1 mm/day thereafter; they were 5 to 6 cm long at day 20. The roots were separated from the corms, washed several times in double-distilled water, homogenized in phosphate buffer 0.1 M, pH 7.0 and centrifuged at 10,000 g for 10 min, then at 35,000 g for 30 min. The supernatant, termed “crude extract”, was used for enzymatic assays. 265 units (u) catalase, 0.9 u lignin peroxidase, 3.3 u o-dianisidine peroxidase, 16 u superoxide dismutase (SOD) and 1.4 u polyphenol oxidase (PPO) were detectable per mg protein in the extract; catalytic efficiency, calculated per mg protein, was 9, 30, 28 and 0.0052, respectively for catalase, lignin peroxidase, o-dianisidine peroxidase, and PPO. Catalase, lignin peroxidase and o-dianisidine peroxidase were sensitive to KCN with IC50 of 0.32, 0.07 and 0.02 mM, respectively; PPO was sensitive to kojic acid with IC50 of 0.03 mM. Thus, quantitatively, the enzymes could be classified as: catalase > SOD > o-dianisidine peroxidase > PPO > lignin peroxidase. In terms of catalytic efficiency, the classification went from lignin peroxidase > o-dianisidine peroxidase > catalase > PPO. Thus the most efficient enzyme studied was lignin peroxidase, using ferulic acid as substrate, while the most abundant enzyme was catalase in C. sativus roots.

کلیدواژه ها:

catalase ، dianisidine peroxidase ، lignin peroxidase ، polyphenol oxidase ، superoxide dismutase