Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Cofactors and Coenzymes

Cofactors and Coenzymes

Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic ions and coenzymes are non-protein organic molecules. Both of these types of helper molecule can be tightly bound to the enzyme or bound only when the substrate binds.

Cofactors and Coenzymes

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic interactions or acid-base reactions. However, amino acids cannot catalyze oxidation-reduction and group transfer reactions and need to be aided by non-protein components called cofactors. Cofactors are also referred to as the chemical teeth of an enzyme.
Cofactors can be metallic ions or organic molecules called coenzymes. These types of helper...

Cofactors and Coenzymes

Cofactors and Coenzymes

Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic ions and coenzymes are non-protein organic molecules. Both of these types of helper molecule can be tightly bound to the enzyme or bound only when the substrate binds.

Redox Reactions

Redox Reactions

Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...

Redox Reactions

Redox Reactions

Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...

Coupled Reactions

Coupled Reactions

Cellular processes such as building and breaking down complex molecules occur through stepwise chemical reactions. Some of these chemical reactions are spontaneous and release energy, whereas others require energy to proceed. Cells often couple the energy-releasing reaction with the energy-requiring one to carry out important cell functions.
Energy in adenosine triphosphate or ATP molecules is easily accessible to do work. ATP powers the majority of energy-requiring cellular reactions. Cells...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Formate Dehydrogenase: The Role of the AMP Cofactor Fragment in Stabilization of the Transition State for Enzyme-Catalyzed Hydride Transfer.

ACS omega·2026

Same author

Guidance for the Knowledge and Skills required for Antimicrobial Stewardship Leaders: an update from the Society for Healthcare Epidemiology of America, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists.

Antimicrobial stewardship & healthcare epidemiology : ASHE·2026

Same author

Enzyme Architecture: Activation of Phosphite Dehydrogenase-Catalyzed Hydride Transfer by NAD<sup>+</sup> Cofactor Fragments.

Biochemistry·2025

Same author

The Role of Protein Side Chains in Enzyme-Activating Conformational Changes: Lessons from Studies on Variant Enzymes.

Chemical reviews·2025

Same author

Bill Jencks' Model for Lifetime Enforced Changes in Reaction Mechanism: A Legacy for Physical Organic Chemistry.

Chemphyschem : a European journal of chemical physics and physical chemistry·2025

Same author

Glycerol 3-Phosphate Dehydrogenase Catalyzed Hydride Transfer: Enzyme Activation by Cofactor Pieces.

Biochemistry·2024

Search research articles

Related Experiment Video

Updated: Jun 5, 2026

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase

Published on: March 19, 2020

The PLP cofactor: lessons from studies on model reactions.

John P Richard¹, Tina L Amyes, Juan Crugeiras

¹Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA. jrichard@buffalo.edu

Biochimica Et Biophysica Acta

|December 25, 2010

Summary

This summary is machine-generated.

Researchers measured the acidity of weak carbon acids like glycine, finding that iminium ion formation significantly lowers acidity. This research offers insights into enzyme catalysis and the role of pyridoxal phosphate (PLP).

More Related Videos

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways

Published on: June 24, 2016

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues

Published on: November 22, 2014

Related Experiment Videos

Last Updated: Jun 5, 2026

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase

Published on: March 19, 2020

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways

Published on: June 24, 2016

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues

Published on: November 22, 2014

Area of Science:

Biochemistry
Organic Chemistry

Background:

Weak carbon acids are crucial in biological systems.
Pyridoxal phosphate (PLP) is a vital enzyme cofactor involved in numerous metabolic reactions.
Understanding the acidity of intermediates is key to elucidating enzymatic mechanisms.

Purpose of the Study:

To experimentally determine the acidity (pK(a)) of glycine and its derivatives.
To investigate the impact of iminium ion formation on carbon acid acidity.
To provide insights into the catalytic mechanisms of PLP-dependent enzymes.

Main Methods:

Development of experimental probes for measuring weak carbon acid acidity.
Determination of pK(a) values for glycine, its derivatives, and iminium ion adducts with 5'-deoxypyridoxal (DPL).
Analysis of the influence of pyridine ring substituents on catalytic efficiency.

Main Results:

The pK(a) of glycine significantly decreases (by 12 units) upon formation of a glycine-DPL iminium ion.
The DPL-stabilized glycyl carbanion exhibits high reactivity, favoring Claisen condensation products.
The study discusses the complex effects of iminium ion formation on carbon acid pK(a).

Conclusions:

The 5'-phosphodianion group of PLP may contribute significantly to enzymatic catalysis by stabilizing transition states.
Binding energy up to 12 kcal/mol can be provided by the PLP 5'-phosphodianion for carbon deprotonation.
These findings enhance our understanding of PLP's role in enzymatic reactions involving carbon acid deprotonation.