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Related Concept Videos

Enzymes02:34

Enzymes

95.1K
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
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Enzyme Kinetics01:19

Enzyme Kinetics

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Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
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Enzyme-linked Receptors01:00

Enzyme-linked Receptors

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Enzyme-linked receptors are proteins that act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of receptors that include the receptor tyrosine kinase (RTK) family. Many growth factors and hormones bind to and activate the RTKs.
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...
86.8K
Enzyme Inhibition01:30

Enzyme Inhibition

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Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure.
92.8K
Introduction to Enzymes01:22

Introduction to Enzymes

32.4K
The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an enzyme-catalyzed reaction. Wilhelm Kuhne coined the term 'enzyme' in 1877 from the Greek words ‘en’ meaning ‘in’ or ‘within’ and ‘zyme’ meaning ‘yeast.’
Most enzymes are proteins that speed up biochemical reactions without being consumed. Enzymes contain one or more active sites that...
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Restriction Enzymes01:11

Restriction Enzymes

36.3K
Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called restriction sites. Such palindromic DNA sequences or inverted repeats are commonly found in regions of functional significance, such as the origin of replication, gene operator sites, and regions containing transcription termination signals.
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
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Related Experiment Video

Updated: Feb 10, 2026

Protocols for Robust Herbicide Resistance Testing in Different Weed Species
10:52

Protocols for Robust Herbicide Resistance Testing in Different Weed Species

Published on: July 2, 2015

15.2K

Old enzymes versus new herbicides.

Tamara L Hendrickson1

  • 1From the Department of Chemistry, Wayne State University, Detroit, Michigan 48202.

The Journal of Biological Chemistry
|May 20, 2018
PubMed
Summary

Microorganisms evolved new pathways to degrade the herbicide atrazine. The AtzE enzyme and AtzG protein, essential for this process, originated from ancient enzymes involved in tRNA aminoacylation, showcasing metabolic repurposing.

Area of Science:

  • Environmental microbiology
  • Biochemistry
  • Molecular evolution

Background:

  • Manmade chemicals like the herbicide atrazine enter the environment.
  • Microorganisms develop new biodegradation pathways in response to pollutants.
  • Understanding these pathways is crucial for bioremediation.

Purpose of the Study:

  • To investigate the enzymatic mechanism of atrazine degradation.
  • To identify the roles of specific proteins, AtzE and AtzG, in this process.
  • To explore the evolutionary origins of the atrazine degradation enzymes.

Main Methods:

  • Enzyme assays to determine catalytic activity.
  • Gene expression analysis to study protein co-regulation.
  • Bioinformatic and comparative genomic analyses to trace evolutionary origins.

More Related Videos

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay
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Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay

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Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System
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Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System

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Related Experiment Videos

Last Updated: Feb 10, 2026

Protocols for Robust Herbicide Resistance Testing in Different Weed Species
10:52

Protocols for Robust Herbicide Resistance Testing in Different Weed Species

Published on: July 2, 2015

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Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay
10:49

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay

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Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System
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Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System

Published on: August 8, 2016

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Main Results:

  • The AtzE enzyme catalyzes a key step in atrazine degradation.
  • Coexpression of the AtzG protein is required for AtzE activity.
  • AtzG and AtzE show evolutionary links to GatC and GatA, involved in tRNA aminoacylation.

Conclusions:

  • Atrazine degradation involves a specific enzyme-protein complex (AtzE-AtzG).
  • The components of this complex have been repurposed from an ancient biological system.
  • This study provides a clear example of metabolic enzyme evolution and adaptation.