Probing protein kinase (CK2) and alkaline phosphatase with CdSe/ZnS quantum dots.
Semiconductor quantum dots (QDs) are used for the optical analysis of casein kinase (CK2) or the hydrolytic activity of alkaline phosphatase (ALP). Two schemes for the analysis of CK2 by a FRET-based mechanism are described. One approach involves the CK2-catalyzed phosphorylation of a serine-containing peptide (1), linked to CdSe/ZnS QDs, with Atto-590-functionalized ATP. The second analytical method involves the specific association of the Atto-590-functionalized antibody to the phosphorylated product. The hydrolytic activity of ALP is followed by the application of phosphotyrosine (4)-modified CdSe/ZnS QDs in the presence of tyrosinase as a secondary reporter biocatalyst. The hydrolysis of (4) yields the tyrosine units that are oxidized by O(2)/tyrosinase to the respective dopaquinone product. The latter quinone units quench the QDs via an electron transfer route, leading to the optical detection of the ALP activity.
Freeman
Ronit
R
Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Finder
Tali
T
Gill
Ron
R
Willner
Itamar
I
D000469:Alkaline Phosphatase / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D019187:Cadmium Compounds / Q000737:chemistry*; D047390:Casein Kinase II / Q000737:chemistry* / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006868:Hydrolysis; D015335:Molecular Probes; D010766:Phosphorylation; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013057:Spectrum Analysis; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
D019187:Cadmium Compounds; D015335:Molecular Probes; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; D047390:Casein Kinase II; D000469:Alkaline Phosphatase; C031238:zinc sulfide