title: Biosynthesis of L-DOPA by Aspergillus oryzae.
abstract: The present investigation deals with the biosynthesis of L-DOPA by parental (GCB-6) and mutant (UV-7) strains of Aspergillus oryzae. There was a marked difference between the mycelial morphology and pellet type of parental and UV-irradiated mutant culture. The mutant strain of A. oryzae UV-6 exhibited pellet-like mycelial morphology and improved tyrosinase activity. Mould mycelium was used for biochemical conversion of L-tyrosine to L-DOPA because tyrosinase is an intracellular enzyme. The mutant was found to yield 3.72 fold higher production of L-DOPA than the parental strain. The mutant strain is stable and D-glc-resistant. The comparison of kinetic parameters was also done which showed the greater ability of the mutant to yield L-DOPA (i.e., Yp/x 40.00+/-0.01 d mg/mg with parent and 182.86+/-0.02a mg/mg in case of mutant). When cultures grown for various incubation periods, were monitored for Qp, Qs and q(p), there was significant enhancement (p < 0.0025-0.005) in these variables by the mutant strain of A. oryzae UV-7 over GCB-6 on all the rates. L-DOPA (3,4-dihydroxy phenyl L-alanine) is a drug of choice in the treatment of Parkinson's disease and myocardium following neurogenic injury.
authors.affiliation: Department of Botany, Government College, Lahore, Pakistan. ikrhaq@yahoo.com
authors.lastname: Ikram-ul-Haq
authors.forename: Sikander
authors.initials: S
authors.lastname: Ali
authors.forename: M A
authors.initials: MA
authors.lastname: Qadeer
mesh_terms: D001236:Aspergillus oryzae / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology; D002478:Cells, Cultured; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D007980:Levodopa / Q000096:biosynthesis* / Q000191:economics; D014442:Monophenol Monooxygenase / Q000378:metabolism* / Q000528:radiation effects; D016296:Mutagenesis; D009154:Mutation; D025282:Mycelium / Q000166:cytology* / Q000235:genetics / Q000528:radiation effects; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D007980:Levodopa; D014442:Monophenol Monooxygenase; D005947:Glucose