Purification and characterization of amylase from local isolate Pseudomonas sp.SPH4

The amylase produced from local isolate Pseudomonas sp. SPH4 was purified by precipitation with 30% saturation ammonium sulphate, followed by ion-exchange chromotography using DEAE-cellulose column, and Gel filtration using Sephacryl S-300 column.The two iso-enzymes (a, b) were purified to (2.83, 3.47) times in the last step with an enzymes yields of (32.36, 76.34)% respectively. Enzyme characterization of the two iso-enzymes indicated that the optimum pH for the two iso-enzymes a and b were (7, 7.5) respectively, while the optimum pH for the iso-enzymes stability were (6.5, 7) respectively. The maximum activity for iso-enzymes (a, b) appeared at 45ºC and stable for 15 min at 30-50ºC and lost approximately 50% of it's activity at rang above 75ºC. Enzyme characterization results showed that the chlorides of silver and mercury had inhibitory effect on enzyme activity, the remaining enzyme activity for the iso-enzymes (a, b) were (46.66, 36.36)% for silver ions and (41.33, 33.63)% for mercury ions at 5 mM respectively, and (28, 28.18)% for silver ions and (25.33, 19.09)% for mercury ions at 10 mM respectively. The iso-enzymes a and b were affected by chelating agent ethylene diamine tetra acetic acid (EDTA) at concentration 2mM the remaining activity (45.33, 43.63)% respectively, and 5mM the remaining activity (28, 28.18)% respectivily, and these iso-enzymes (a, b) refered to metalloenzymes. The iso-enzymes (a, b) were kept their activity when treated by reducing agent (2-mercaptoethanol) at 2 mM the remaining activity (92, 92.72)% respectively, and 5 mM the remaining activity (85.3, 89.09)% respectivily. The iso-enzymes (a, b) were kept their activity when treated by phenyl methyl sulphonyl fluoride (PMSF) at concentration 1mM the remaining activity (93.33, 90.90)% respectivily,and 5 mM the remaining activity (90.66, 87.27)% respectivily, and these indicated that these iso-enzymes didnot referred to serineamylases group.