Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.2.1.17 (
lysozyme
)
21,489
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Photosensitized
electron transfer are studied in three systems:
lysozyme
, its inhibitors (oligosaccharides) and their enzyme-inhibitor complexes. Electron donors were either tryptophane amino acid residues of
lysozyme
or tryptophane. It is shown that N-acetyl group of inhibitor molecules is a single electron--acceptor group in the inhibitor molecule as well as in the
lysozyme
-inhibitor complex. It is stated that the localization of unpaired electrons in the mixtures of
lysozyme
modification products and substrate--inhibitors depends on the state of enzyme molecule.
...
PMID:[Electron paramagnetic resonance study of photosensitized transport and localization of electrons in enzyme-substrate complexes. Lysozyme and its inhibitor]. 17 1
Photosensitized
protein oxidation is a promising tool for medical procedures such as photochemical tissue bonding (PTB). We have recently reported that the binding of rose Bengal, a sensitizer employed in PTB, to
lysozyme
modulates the photooxidation and crosslinking of this protein. In this work we examined the photooxidation and crosslinking of
lysozyme
mediated by riboflavin (RF) an endogenous sensitizer also employed in PTB. We hypothesized that since RF does not bind strongly to proteins, the mechanism(s) and extent of enzymatic inactivation, amino acid modification and protein crosslinking would be dependent on the presence of O
2
, and differ to that induced by rose Bengal. This hypothesis was tested using UV-visible spectrophotometry, isothermal titration calorimetry (ITC), SDS-PAGE gels, quantification of amino acid consumption, and LC-MS analysis of sites of modification and crosslinks. Under N
2
, limited damage was detected arising from type 1 (radical) chemistry with formation of specific intra- (Tyr20-Tyr23) and inter- (Tyr23-Trp108) molecular crosslinks. In contrast, the presence of O
2
triggered extensive protein damage through mixed type 1 and type 2 (
1
O
2
) mechanisms leading to Trp, Met, Tyr and His oxidation, loss of enzymatic activity and protein dimerization. LC-MS analysis provided evidence for crosslinking via radical-radical recombination reactions (Trp28-Tyr53), and secondary reactions involving nucleophilic attack of the side-chain amine of Lys116 on carbonyl groups. Overall, this behavior is in marked contrast to that detected with rose Bengal indicating that the mechanisms and sites of photo-oxidative damage, and consequences for protein function, can be modulated by the choice of sensitizing dye.
...
PMID:Photo-oxidation of lysozyme triggered by riboflavin is O
2
-dependent, occurs via mixed type 1 and type 2 pathways, and results in inactivation, site-specific damage and intra- and inter-molecular crosslinks. 3214 79
