... rate of TH activity as afunction of the concentration of l-dopa cofactor addedto the assay mixture. R3-1501 – extracts have a highTH activity, almost independent of the addition of l-dopa cofactor, ... DO activity at pH 7 and 0.02% SDS.Fig. 3. Dependence of the TH activity of extracts of R3 and thetwo mutant strains on the presence of cofactor,L-dopa. (n) R3; (d)R3-0337 – which only expresses ... Herna´ndez-Romero1, Antonio Sanchez-Amat1 and Francisco Solano21 Department of Genetics and Microbiology, 2 Department of Biochemistry and Molecular Biology B, University of Murcia, SpainPolyphenol oxidases...