The temperature Effects on Activity of Beta-Cyanoalanine Synthase enzyme and Cyanide metabolism in two Apple cultivars FUJI and ABBASI MASHHAD

Cyanide is a Co-product of ethylene biosynthesis in higher plants via the ACC pathway.In certain physiological, such as fruit ripening, flower senescence, flooding, drought,pathogen infection, ozone, UV radiation and chilling, ethylene biosynthesis is greatlyinduced. Cyanide is a harmful ion, hazardous to life, which forms a very stable complex with the active site metal (e.g., Fe and Mg) in enzymes, thereby inhibiting vital functions, in cells such as respiration, carbon fixation, and nitrate reduction. Many plants have the ability to produce HCN; more than 2,000 species have been defined as cyanogenic.In higher plants the key enzyme to detoxify HCN is L-3-cyanoala ninsynthase (EC.4.4.1.9). In order to analyze Cyanide metabolism in relation to ethylene biosynthesis in two apple cultivar (fuji and Abbasi Mashhad) a factorial experiment was conducted in splitplotarranged based on randomized complete block design with different replication. Thequantitative and qualitative characteristics were evaluated including ethylene productionCyanide metabolism and activity of Beta–CAS in four level of temperature (-2, 0, +2, +4).Beta-CAS synthase enzyme can be assessed by measuring the sulfide that is formed duringthe reaction between HCN and L. cysteine colorimetrically. In the following study it was observed that the tissue with the highest Beta-CAS enzyme activity, has the most ethylene production level. The existence of an appropriate link between ethylene and cyanic biosynthesis and Cyanide metabolism was clear. This showed that ethylene can increase Cyanide metabolization capacity.