title: Comparison of nitrophenylethyl and hydroxyphenacyl caging groups.
abstract: Nitrophenylethyl (NPE)- and hydroxyphenacyl (HPA)-caged nucleotides were employed in a time-resolved Fourier transform IR spectroscopy study on Ras-catalyzed guanosine triphosphate (GTP) hydrolysis. A fast kinetic component was observed following the photolysis of NPE-caged nucleotides in the NPE-GTP-Ras complex. However, this kinetic component was not observed in the HPA-GTP-Ras experiment. This fast kinetic component was likely due to a chemical reaction between Ras and the detached caging group, nitrosoacetophenone. This communication serves as a note of caution in interpreting spectral changes and kinetic behavior of the enzymatic systems employing NPE-caged compounds.
authors.affiliation: Department of Chemistry, Room 220, Melvin Calvin Laboratory, University of California, Berkeley, CA 94720, USA.
authors.forename: X
authors.initials: X
authors.lastname: Du
authors.forename: H
authors.initials: H
authors.lastname: Frei
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry*; D006868:Hydrolysis; D066298:In Vitro Techniques; D009603:Nitroso Compounds / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013873:Thionucleotides / Q000737:chemistry*; D018631:ras Proteins / Q000737:chemistry
chemical_list: D009603:Nitroso Compounds; D013873:Thionucleotides; C061507:P(3)-1-(2-nitro)phenylethylguanosine 5'-O-triphosphate; D006160:Guanosine Triphosphate; D018631:ras Proteins