title: 5'-Phosphodiesterase (5'-PDE) from germinated barley for hydrolysis of RNA to produce flavour nucleotides.
abstract: 5'-Phosphodiesterase (5'-PDE) is an enzyme that hydrolyses RNA to a mixture of ribonucleotides, from which the flavour enhancers, 5'-guanosine monophosphate (5'-GMP) and 5'-inosine monophosphate (5'-IMP) can be isolated. In the present work, 5'-PDE was extracted and partially purified from germinated barley seeds. 5'-PDE activity was monitored using bis-p-nitrophenyl phosphate as the substrate. The enzyme acts on the substrate and releases the p-nitrophenol, which is measured at 420 nm. Ultrafiltration using a polysulfone membrane having molecular weight cut off (MWCO) of 20 kDa gave 12-fold concentration. Further purification using ammonium sulphate gave 18-fold concentration. Heat shock for 15 min at 60 degrees C after the ultrafiltration enhanced the concentration of 5'-PDE 9.10 fold, while a similar treatment after ammonium sulphate treatment enhanced it by 17.83-fold. The enzyme had a pH optimum of 5, and was stable at 0 degrees C. This partially purified enzyme could be used for hydrolysis of RNA to produce 5'-GMP and 5' adenosine monophosphate, a precursor of 5'-IMP.
authors.affiliation: Food and Fermentation Technology Department, Institute of Chemical Technology, University of Mumbai, Matunga, Mumbai, 400 019, India.
authors.forename: Anand J
authors.initials: AJ
authors.lastname: Deoda
authors.forename: Rekha S
authors.initials: RS
authors.lastname: Singhal
mesh_terms: D000645:Ammonium Sulfate; D004795:Enzyme Stability; D005421:Flavoring Agents / Q000378:metabolism*; D018525:Germination; D006157:Guanosine Monophosphate / Q000378:metabolism; D001467:Hordeum / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007291:Inosine Monophosphate / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000302:isolation & purification* / Q000378:metabolism*; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D005421:Flavoring Agents; D009711:Nucleotides; D007291:Inosine Monophosphate; D012313:RNA; D006157:Guanosine Monophosphate; D010727:Phosphoric Diester Hydrolases; D000645:Ammonium Sulfate