How Do Enzymes Deactivate After Signal Ends?

  • Thread starter Ahmed Abdullah
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In summary, the presence of signal molecules can activate enzymes through phosphorylation, and when the signal stops, these enzymes can continue their function. However, enzymes can also be deactivated through the action of phosphatases, which can remove phosphates from proteins and other phosphorylated molecules. These enzymes are always present and do not need to be synthesized. In some cases, the product of the enzyme reaction can act as a cofactor for the phosphatase enzyme, leading to a negative feedback loop.
  • #1
Ahmed Abdullah
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In the presence of the signal molecules, cascades of enzyme activation take place usually by phosphorylation. When signal ceases activated enzymes (phosphorylated or dephosphorylated) are still there, so they can go on doing what they were doing before. My question is how this enzymes are deactivated after the signal ends? I am looking for basic mechanism (schematic).
 
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  • #2
There are enzymes called phosphatases that can remove phosphates from proteins and other phosphorylated molecules. In fact, most post-translational modifications of proteins can be reversed by some enzymes (e.g. deubiquitinases remove ubiquitin, deacetylases remove acetylation, etc.).
 
  • #3
Ygggdrasil said:
There are enzymes called phosphatases that can remove phosphates from proteins and other phosphorylated molecules. In fact, most post-translational modifications of proteins can be reversed by some enzymes (e.g. deubiquitinases remove ubiquitin, deacetylases remove acetylation, etc.).

Are these phosphatase still there even when no signal is present?
Or they need to be activated or synthesized when a particular signal ends (seems very unlikely)?
 
  • #4
Phosphatases are always there they don't need to be synthesized. May be when there is too much product from the enzyme reaction it can act as cofactor for Phosphatase enzymes and reverse the reaction. Like negative feedback!
 
  • #5


Enzymes are essential biological molecules that play a critical role in regulating biochemical reactions within cells. They act as catalysts, increasing the rate of chemical reactions without being consumed in the process. Enzymes are tightly regulated to ensure that they are only active when needed and do not cause harm to the cell.

The activation of enzymes is often triggered by the binding of specific signal molecules, such as hormones or neurotransmitters, to their respective receptors on the cell surface. This binding initiates a signaling cascade that ultimately leads to the activation of enzymes.

When the signal ends, the enzymes must be deactivated to prevent them from continuously catalyzing reactions. There are several ways in which enzymes can be deactivated after the signal ends:

1. Dephosphorylation: Many enzymes are activated by phosphorylation, which involves the addition of a phosphate group to the enzyme. This process is reversible, and the phosphate group can be removed by specific enzymes called phosphatases. When the signal ends, these phosphatases are activated, and they remove the phosphate group from the enzyme, rendering it inactive.

2. Proteolytic cleavage: Some enzymes are synthesized as inactive precursors that require proteolytic cleavage to become active. When the signal ends, the production of these proteases is inhibited, preventing the activation of the enzymes.

3. Negative feedback: In some cases, the end product of a reaction catalyzed by an enzyme can act as a signal to inhibit the enzyme's activity. This is known as negative feedback, and it helps to regulate the enzyme's activity and prevent it from becoming overactive.

4. Disassembly: Some enzymes are composed of multiple subunits that come together to form an active enzyme. When the signal ends, these subunits can dissociate, rendering the enzyme inactive.

In summary, enzymes can be deactivated after the signal ends through various mechanisms, including dephosphorylation, proteolytic cleavage, negative feedback, and disassembly. These processes ensure that enzymes are only active when needed and are tightly regulated to maintain cellular homeostasis.
 

What are enzymes and how do they work?

Enzymes are proteins that act as catalysts in biochemical reactions. They speed up the rate of a reaction by lowering the activation energy required for the reaction to occur. Enzymes work by binding to specific molecules, called substrates, and converting them into products.

How do enzymes deactivate after a signal ends?

Enzymes are deactivated after a signal ends through a process called feedback inhibition. This occurs when the end product of a reaction binds to the enzyme, changing its shape and preventing it from binding to its substrate. This stops the enzyme from continuing to catalyze the reaction.

What factors can affect the deactivation of enzymes?

The deactivation of enzymes can be affected by various factors such as temperature, pH, and the presence of inhibitors. High temperatures can denature enzymes, changing their shape and preventing them from functioning. Extreme pH levels can also alter the shape of enzymes, affecting their ability to bind to substrates. Inhibitors can also bind to enzymes and prevent them from catalyzing reactions.

How does the body regulate enzyme activity?

The body regulates enzyme activity through various mechanisms such as feedback inhibition, enzyme synthesis and degradation, and allosteric regulation. Feedback inhibition helps to maintain a balance of enzyme activity by deactivating enzymes when their end product is no longer needed. Enzyme synthesis and degradation control the amount of enzymes present in the body, while allosteric regulation involves the binding of molecules to specific sites on the enzyme, which can either activate or deactivate its function.

What happens if an enzyme is unable to deactivate after a signal ends?

If an enzyme is unable to deactivate after a signal ends, it can lead to an accumulation of the end product and an imbalance in the biochemical pathways. This can result in various health issues and diseases. In some cases, it can also lead to the malfunctioning of other enzymes and disrupt normal cellular processes.

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