title: Probing biocatalytic transformations with CdSe-ZnS QDs.
abstract: CdSe/ZnS QDs enable the optical probing of the biocatalytic oxidation of tyrosine derivatives and of the scission of peptides by thrombin. CdSe/ZnS QDs were modified with tyrosine methyl ester or with a tyrosine-containing peptide. The tyrosine units were reacted with tyrosinase/O2 to yield the respective l-DOPA and quinone derivatives. The luminescence of QDs modified by the enzyme-generated quinone units is quenched. The quinone-functionalized peptide associated with the QDs was cleaved by thrombin, a process that restored the luminescence of the QDs.
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Ron
authors.initials: R
authors.lastname: Gill
authors.forename: Ronit
authors.initials: R
authors.lastname: Freeman
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Xu
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
authors.forename: Shira
authors.initials: S
authors.lastname: Winograd
authors.forename: Itzik
authors.initials: I
authors.lastname: Shweky
authors.forename: Uri
authors.initials: U
authors.lastname: Banin
mesh_terms: D015374:Biosensing Techniques; D001711:Biotransformation; D019187:Cadmium Compounds / Q000737:chemistry*; D002384:Catalysis; D005453:Fluorescence; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D014443:Tyrosine / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D014443:Tyrosine; C058667:cadmium selenide; D014442:Monophenol Monooxygenase; C031238:zinc sulfide; D010100:Oxygen