Pii: S0968-0896(98)00173-4
نویسندگان
چکیده
ÐA number of model compounds resembling the fundamental bonding patterns of residual kraft lignin, including a series of stilbenes, were incubated with laccase from Trametes versicolor in the presence and absence of deligni®cation `mediators' ABTS and HBT. The condensed kraft lignin model compounds seem to undergo initial degradation by laccase mainly via benzylic oxidation, demethylation and hydroxylation reactions. Phenolic 5-50, diphenylmethane and a-5 lignin models were found to be degraded mainly via side-chain oxidation reactions. Among the models studied, a phenolic stilbene was found to be the most reactive, yielding several products showing side-chain oxidation/transposition, demethoxylation and hydroxylation reactions. Non-phenolic 5-50, diphenylmethane and stilbene model compounds were found unreactive even in the presence of the laccase-mediator system. # 1998 Elsevier Science Ltd. All rights reserved.
منابع مشابه
Pii: S0968-0896(98)00247-8
ÐThe theory of absolute reaction rates suggests that enzymes, like other catalysts, can enhance the rate of a reaction only to the extent that they bind the altered substrate in the transition state (S{) more tightly than they bind the substrate in the ground state (S). ES dissociation constants commonly fall in the physiological range, but recent kinetic studies indicate that formal ES{ dissoc...
متن کاملPii: S0968-0896(98)00211-9
ÐN-Benzoyloxy-2-thiopyridone (12) was shown to induce single-strand nicks in duplex DNA upon irradiation with visible light (l&350 nm). This ®nding led to the design of a series of compounds, in which an acridinyl nucleus was covalently linked to the N-benzoyloxy-2-thiopyridone unit. These conjugates (15, 16, 17 and 18) were synthesized and evaluated as novel DNA photocleaving reagents. Optimal...
متن کاملPii: S0968-0896(97)00137-5
-Philanthotoxins are noncompetitive inhibitors of the nicotinic acetylcholine receptor and the various glutamate r<.~ceptors. Analogues carrying photoaffinity labels, fluorine atoms for solid-state NMR studies of ligand/receptor interaction, and large head groups such as porphyrins and planar bulky aromatic rings (BIG analogues) for clarifying mode of entry and orientation of analogues in recep...
متن کاملPii: S0968-0896(98)00262-4
Ðb-Carboline-benzoquinolizidine plant alkaloid deoxytubulosine (DTB) was evaluated and assessed for the ®rst time for its biochemical and biological activity employing the biomarker dihydrofolate reductase (DHFR) (5,6,7,8-tetrahydrofolate: NADP oxidoreductase, EC 1.5.1.3) as the probe enzyme, a key target in cancer chemotherapy. DHFR, employed in the present investigations was puri®ed from Lact...
متن کاملPii: S0968-0896(98)00129-1
ÐAllatostatins are 6±18 amino acid peptides synthezed by insects to control production of juvenile hormones, which in turn regulate functions including metamorphosis and egg production. Four insect allatostatin neuropeptide analogues incorporating turn-promoting pseudopeptide moieties in the region responsible for biological activity were prepared by solid phase peptide synthetic methods. Bioas...
متن کامل