TY  - JOUR
A1  - Rosenkranz, Peter
A1  - Schmidt, Hartmut
T1  - On the mechanism of the acridine orange sensitized photodynamic inactivation of lysozyme. II. Kinetics in presence of N-acetylglucosamine
T2  - Zeitschrift für Naturforschung, C
N2  - The photodynamic deactivation of lysozyme in presence of acridine orange is caused by a reaction between singlet oxygen formed via the dye triplet state and the protein. In order to identify the region where the singlet oxygen reacts with the protein we have investigated the kinetics of the deactivation in presence ofthe inhibitor of the enzymatic reaction N-acetylglucosamine (GlcNAc). The overall experimental rate constant becomes slower with increasing saccharide concentrations. As we can exclude experimentally that this kinetical effect is caused in presence of the saccharide by a physical quenching of singlet oxygen or of the dye triplet state it has to be assumed that GlcNAc protects the surrounding of its bindings place at subsite C of the enzymatic center sterically against an attack of singlet oxygen. In this region three tryptophan residues are located, which could be sensitive against singlet oxygen. Surprisingly, however, it has been found that only those species are protected, in which a second saccharide molecule is bound to the protein, probably at subsite E at the enzymatic center, where no sensitive amino acid side chains are located.
KW  - Photodynamic Effect
KW  - Singlet Oxygen
KW  - Lysozyme
KW  - Acridine Orange
KW  - Kinetics
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/72095
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-720954
SN  - 0939-5075
SN  - 1865-7125
VL  - 31.1976
IS  - 11-12
SP  - 679
EP  - 682
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -