سنجش فعاليت آنزيم ال - گلوتاميتاز دربقاياي گياهي، لاشبرگ هاي جنگلي و كودهاي آلي

چكيده انگليسي :

The Assay of L glutaminase Activity in Plant Residues Forest Litters and Organic Fertilizers Zohre Mohammadi Feshkelposhte z mohammadi@ag iut ac ir 21 Dec 2013 College of Agriculture Isfahan University of Technology Isfahan 84156 83111 Iran Language FarsiDegree M ScFarshid Nourbakhsh Prof farshid@cc iut ac irAbstractManagement of plant residues and organic matters is one of the most important ways to improve soilfertility in sustainable agriculture Decomposition of organic wastes supplies necessary elements to plantsvia mineralization processes Nitrogen defficiency limits plant growth Nitrogen Mineralization provideplants and other organisms with available N and hence plays an important role in plant nutrition reducingdeficiency symptoms and ecosystem functioning L glutaminase mineralizes nitrogen with catalyzingbreaking of non peptide C N linkage in L glutamine amino acid This results in changing L glutamine toL glutamic acid and ammonium This study aims to 1 identify the optimum condition of the assay of L glutaminase activity for plant residues forest litters and organic ammendments 2 study the effect of air drying and freezing of plant residues on L glutaminase and 3 determine the kenetics and thermodynamicsparameters of L glutaminase in plant residues For these purposes Acer velotonium and Gleditschiacaspica litters cow manure and sewage sludge were sampled Fresh residues were pulverised then kept at4 C Freezed residues were amended with liquid nitrogen and kept at 4 C temprature Litters fertilizerand a part of plant residues were air dried at room tempratore passed through a 1mm sieve and kept at 4 C The effect of incubation time sample amount incubation pH incubation temperature and substrateconcentration were studied In plant residue we studied the effect of freezing and air drying on L glutaminase activity Then kinetics and thermodynamics parameters were determined Lineartransformations of michaelis menten equation including lineweaver Burk Eidie Hofstee and Hones wolfwere used Arhenius and Eyring equations were performed for determining the activation energy andactivation enthalpy respectively The optimum conditions of L glutaminase activity assay were 2 hours ofincubation time at 37 C 0 1g sample amount pH 10 and 50mM substrate concentration Freezing andairdrying decreased L glutaminase activity in plant residues and airdrying decreased L glutaminase activitymore than the freezing The maximum velocity of L glutaminase activity was ranged from 117 7 to 3611 6 g NH4 N g 1 h 1 The Km values varied from 11 1 to 83 3 mM The activation energy ranged 28 to 68kJlmol for cow manure and airdried alfalfa respectively The minimum and maximum enthalpy ofactivation found in cow manure and airdried alfalfa respectively The average of Q10 values were rangedfrom 1 27 to 2 32 The method used in determination of L glutaminase activity in soil samples can be usedin organic materials with minimum modifications The responses of materials of different origin toincubation conditions were dissimilar similar responses were observed in each type including plantresidues organic fertilizers and forest litters Keywords L glutaminase Kinetics and thermodynamics Plant residue Forest litter Organic fertilizers

محمدي فشكل پشته، زهره

سنجش فعاليت آنزيم ال - گلوتاميتاز دربقاياي گياهي، لاشبرگ هاي جنگلي و كودهاي آلي

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