title: Purification and characterization of RNA allied extracellular tyrosinase from Aspergillus species.
abstract: Production of L-DOPA, an anti-Parkinson's drug, using biological sources is widely studied in which tyrosinase is known to play a vital role. Tyrosinase is an omnipresent type 3 copper enzyme participating in many essential biological functions. Understanding properties of tyrosinase is essential for developing useful tyrosinase-based applications. Hence, extracellular tyrosinase from Aspergillus flavus UWFP 570 was purified using ammonium sulphate precipitation and DEAE ion exchange chromatography up to 8.3-fold. Purified protein was a riboprotein in nature containing significant amount of RNA which was confirmed colorimetrically and by electrophoresis. Removal of RNA reduced the activity and altered the conformation of tyrosinase as suggested by spectroflurometric results. Optimum pH and temperature of this 140 kDa protein were 7 and 40 °C, respectively. Copper sulphate and magnesium chloride enhanced the activity whereas in contrast FeCl₃ inhibited the activity completely. Purified tyrosinase transformed L-tyrosine (5 mM) to L-DOPA within 5 h.
authors.affiliation: Department of Biotechnology, Shivaji University, Kolhapur, 416 004, India.
authors.forename: Shrirang
authors.initials: S
authors.lastname: Inamdar
authors.forename: Swati
authors.initials: S
authors.lastname: Joshi
authors.forename: Vishwas
authors.initials: V
authors.lastname: Bapat
authors.forename: Jyoti
authors.initials: J
authors.lastname: Jadhav
mesh_terms: D001231:Aspergillus flavus / Q000201:enzymology*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D007980:Levodopa / Q000737:chemistry / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012313:RNA / Q000737:chemistry; D013696:Temperature; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism
chemical_list: D014443:Tyrosine; D007980:Levodopa; D012313:RNA; D014442:Monophenol Monooxygenase