Related Experiment Video
Updated: May 13, 2026
07:59
A High-Yield Streptomyces Transcription-Translation Toolkit for Synthetic Biology and Natural Product Applications
Published on: September 10, 2021
Transketolase reaction under credible prebiotic conditions
Ronald Breslow1, Chandrakumar Appayee
1Department of Chemistry, Columbia University, New York, NY 10027, USA. rb33@columbia.edu
Summary
Prebiotic chemistry reveals cyanide ion, not thiamine pyrophosphate (TPP), catalyzed early transketolase reactions. This suggests simpler, cyanide-driven sugar synthesis before the evolution of TPP-dependent enzymes.
Area of Science:
- Biochemistry
- Prebiotic Chemistry
- Astrobiology
Background:
- Modern transketolase reactions utilize thiamine pyrophosphate (TPP) as a crucial cofactor.
- Understanding early biochemical pathways is key to understanding the origin of life.
Purpose of the Study:
- To investigate alternative catalysts for transketolase reactions under prebiotic conditions.
- To explore the role of cyanide ion in early sugar metabolism.
Main Methods:
- Simulated prebiotic conditions were used to test cyanide ion as a catalyst for transketolase.
- Fructose and glyceraldehyde were reacted in the presence of cyanide ion.
Main Results:
- Cyanide ion effectively catalyzed the conversion of fructose and glyceraldehyde to erythrose and xylulose.
- The products were identical to those formed in modern TPP-catalyzed reactions, but lacked phosphate groups.
- Cyanide demonstrated higher catalytic efficiency than TPP in simple solution.
Conclusions:
- Cyanide ion likely served as an early catalyst for transketolase reactions before the advent of TPP.
- The evolution of TPP-dependent enzymes may have been driven by cyanide's toxicity to metalloproteins in an oxygenated atmosphere.
More Related Videos
Related Concept Videos
01:24Other Glycolytic Pathways
The pentose phosphate pathway (PPP) operates in parallel with glycolysis, facilitating the metabolism of both pentoses and glucose. This pathway consists of two distinct phases: the oxidative and non-oxidative phases. While it does not directly generate ATP, the intermediates formed during the process can integrate into glycolysis, contributing to cellular energy metabolism when required.Oxidative Phase: NADPH ProductionThe oxidative phase of the pentose phosphate pathway is primarily...
01:28Carbon-dioxide Fixation
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
01:14Keto–Enol Tautomerism: Mechanism
The keto and enol forms are known as tautomers and they constantly interconvert (or tautomerize) between the two forms under acid or base catalyzed conditions. Both the reactions involve the same steps—protonation and deprotonation— although in the reverse order.
01:21Glycolysis: Preparatory Phase
In cellular metabolism (the complete breakdown of glucose to extract energy), glycolysis is the first step. Glycolysis takes place in the cytoplasm of both prokaryotic and eukaryotic cells. Glucose enters heterotrophic cells in two ways. One method is through secondary active transport, where the transport takes place against the glucose concentration gradient. The other mechanism uses a group of integral proteins called GLUT proteins, also known as glucose transporter proteins. These...
01:27Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols.
01:20Fates of Pyruvate
Pyruvate is the end product of glycolysis, where glucose is oxidized to pyruvate, simultaneously reducing NAD+ to NADH. Two molecules of ATP are also produced by substrate-level phosphorylation.
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...