Catalysis of Nontronite in Phenols and Glycine Transformations

Abstract

Abstract--The catalytic power of Ca-nontronite (0.2-2 urn) for the polycondensation of phenols and glycine and the associated reactions that involve the ring cleavage of phenols and the deearboxylation and deamination of glycine was studied in systems free of microbial activity. At the end ofa 90-hr reaction period, the amount of CO2 released from the Ca-nontronite-glycine-pyrogalloI, Ca-nontronite-glycinecatechol, and Ca-nontronite-glyeine-hydroquinone systems were 5.1, 8.7, and 11.6 times higher, respectively, than those from the respective nontronite-free systems, showing the catalytic role of Ca-nontronite in the ring cleavage of phenols and the decarboxylation of glycine. The release of CO2 and NH3 from the Ca-nontronite-glycine system revealed that Ca-nontronite can catalyze decarboxylation and deamination of glycine. The ability of Ca-nontronite to catalyze the deamination of glycine was substantially enhanced by the presence of a phenol. The visible absorbances at both 472 and 664 nm of the supernatants, the total yields of N-containing humic polymers, and the fractions of glycine converted to nitrogenous polymers indicated that polycondensation of glycine and phenol was greatly catalyzed by Ca-nontronite. The total N-containing humic polymers formed in the systems decreased in the order: Ca-nontroniteglycine-pyrogallol > Ca-nontronite-glycine-cateehol > Ca-nontronite-glycine-hydroquinone > glycinepyrogallol > glycine-hydroquinone > glycine-catechol. The infrared and electron spin resonance spectra of humie acid (HA) and fulvic acid (FA) formed in the supernatants of the reaction systems were quite similar to those of soil HA and FA. The catalytic power of Ca-nontronite in affecting the ring cleavage of phenols, deamination and decarboxylation of amino acids, and formation ofhumic substances derived from phenols with amino acids in soils and the related environments thus merits attention.

Cleavage of 14C-labeled glycine and its polycondensation with pyrogallol as catalyzed by birnessite

“…The data revealed that birnessite greatly promoted the ring cleavage of pyrogallol and decarboxylation and dealkylation of glycine. The present study has extended the findings of the previous experiments (Wang andHuang, 1987, 1992) by showing the relative contribution of glycine and pyrogallol to the release of CO 2 . Based on the ratio of the unlabeled to labeled glycine present in the reaction systems and the total mass of 14 CO 2 released from respective reaction conditions (Table 2), the amounts of CO 2 derived from the decarboxylation plus dealkylation of glycine and from the ring cleavage of pyrogallol in the BPG system were calculated and presented in Table 3.…”

“…An apparatus described by Wang (1991) was used in this experiment to determine the released 14 CO 2 and CO 2 . The suspension in the vial as described above was transferred to the autoclaved 500 ml, widemouth Erlenmeyer polycarbonate flask.…”

The effect of smectite composition on the catalysis of peptide bond formation

“…This could lead to the decomposition of both reactant and reaction products. The same clay has been reported to catalyze oxidative decomposition of glycine producing NH 3 and CO 2 (Wang 1991). The location of net negative layer charge (octahedral and tetrahedral sheets) is probably very important for the orientation of amino acid zwitterions interacting with the clay particle edges.…”

The Fe-Rich Clay Microsystems in Basalt-Komatiite Lavas: Importance of Fe-Smectites for Pre-Biotic Molecule Catalysis During the Hadean Eon

“…The chemical reactions involving electron transfer are particularly efficient in the presence of Fe 2+ -bearing clay minerals (Wang 1991;Parthasarathy et al 2003). Iron-containing clay minerals are ubiquitously present in subsurface environments and structural Fe 2+ can be formed from microbial Fe 3+ reduction.…”