Stability of DL-Glyceraldehyde under Simulated Hydrothermal Conditions: Synthesis of Sugar-like Compounds in an Iron(III)-Oxide-Hydroxide-Rich Environment under Acidic Conditions. | LitMetric
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
Published: November 2022
AI Article Synopsis
Article Abstract
Researchers have suggested that the condensation of low-molecular-weight aldehydes under basic conditions (e.g., pH > 11) is the prebiotic reaction responsible for the abiotic formation of carbohydrates. It has also been suggested that surface hydrothermal systems were ubiquitous during the early Archean period. Therefore, the catalysis of prebiotic carbohydrate synthesis by metallic oxide minerals under acidic conditions in these environments seems considerably more probable than the more widely hypothesized reaction routes. This study investigates the stability of DL-glyceraldehyde and its reaction products under the simulated conditions of an Archean surface hydrothermal system. The Hveradalur geothermal area in Iceland was selected as an analog of such a system. HPLC-ESIMS, UV−Vis spectroscopy, Raman spectroscopy and XPS spectroscopy were used to analyze the reaction products. In hot (323 K) and acidic (pH 2) solutions under the presence of suspended iron(III) oxide hydroxide powder, DL-glyceraldehyde readily decomposes into low-molecular-weight compounds and transforms into sugar-like molecules via condensation reactions.
Researchers have suggested that the condensation of low-molecular-weight aldehydes under basic conditions (e.g., pH > 11) is the prebiotic reaction responsible for the abiotic formation of carbohydrates.
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Substrate specificity in the aldo-keto reductase (AKR) superfamily is determined by three mobile loops positioned at the top of the canonical (α/β)(8)-barrel structure. These loops have previously been demonstrated to be modular in a well-studied class of AKRs, in that exchanging loops between two similar hydroxysteroid dehydrogenases resulted in a complete alteration of substrate specificity (Ma,H. and Penning,T.
Aldose reductase (ALR2) shows a strong specificity for its nucleotide coenzyme, binding NADPH much more tightly than NADH (KD of < 1 microM versus 1.2 mM respectively). Interactions responsible for this specificity include salt linkages between the highly conserved residues Lys-262 and Arg-268, and the 2'-phosphate of NADP(H).
In the insulin-secreting, glucose-insensitive islet cell subclone RINm5F, the distribution of protein kinase C (PKC) activity in the cytosol and membrane fractions was determined, and the activation of the enzyme, as reflected in its translocation to the membrane fraction, was characterized in conjunction with insulin release. DL-Glyceraldehyde (15 mM) evoked a rapid redistribution of PKC from the cytosol to the membrane fraction; insulin release increased concomitantly. When monitored over 5 min with 15 mM glyceraldehyde, membrane stabilization of PKC reached a maximum at 30 s and decreased thereafter; insulin release occurred at a high rate for the first 15 s and diminished thereafter.
