Regulatory enzymes are crucial as they catalyze biochemical reactions and control pathway activities through responses to specific biomolecules, primarily regulating the production of hormones. They can undergo activation or deactivation through mechanisms such as allosteric modulation or covalent modification, notably phosphorylation, allowing for precise control of reaction speeds. Overall, these enzymes ensure that metabolic pathways operate efficiently to meet the cellular demands.

1. Regulatory enzymes
NAME:K GUNA ADITYA VARDHAN
REG NO:17BCB0060
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2. REGULATORY ENZYMES
• The enzymes which catalyse chemical reactions again and
again are called regulatory enzymes.
A regulatory enzyme is an enzyme in a biochemical pathway which,
through its responses to the presence of certain other biomolecules,
regulates the pathway activity. This is usually done for pathways
whose products may be needed in different amounts at different
times, such as hormone production. Regulatory enzymes exist at high
concentrations (low Vmax) so their activity can be increased or
decreased with changes in substrate concentrations.
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3. Generally, it is considered that a hyperbolic structured protein in
specific media conditions is ready to do its task, it is active, but some
spe deactivation, are responsible for the regulation of some
metabolism pathways. Regulatory enzymes are commonly the first
enzyme in a multienzyme system: the product of the reaction
catalyzed by the first enzyme is the substrate of the second enzyme,
so the cell can control the amount of resulting product by regulating
the activity of the first enzyme of the pathway.
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4. There are many strategies of activation and deactivation of
regulatory enzymes. Regulatory enzymes require an extra
activation process and need to pass through some modifications
in their 3D in order to become functional, for instance, catalyzing
enzymes (regulatory enzymes). The regulation of the activation
of these catalyzing enzymes is needed in order to regulate the
whole reaction speed, so that it is possible to obtain the amount
of product required at any time, that makes regulatory enzymes
have a biological importance. Therefore, regulatory enzymes,
by its controlled activation and are of two types: allosteric
enzymes and covalently modulated enzymes; however, an
enzyme can combine both types of regulation.
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5. Allosteric enzymes
This type of enzymes presents two binding sites: the substrate of the
enzyme and the effectors. Effectors are small molecules which
modulate the enzyme activity; they function through reversible, non-
covalent binding of a regulatory metabolite in the allosteric site (which
is not the active site). When bound, these metabolites do not
participate in catalysis directly, but they are still essential: they lead to
conformational changes in a concrete part of the enzyme. These
changes affect the overall conformation of the active site, causing
modifications on the activity of the reaction.
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8. COVALENTLY MODULATED ENZYMES
Here, the active and inactive form of the enzymes are altered due
to covalent modification of their structures which is catalysed by
other enzymes. This type of regulation consists of the addition or
elimination of some molecules which can be attached to the
enzyme protein. The most remarkable covalent modification
is phosphorylation. Serine, Threonine and Tyrosine are common
amino acids that participate in covalent modifications and are used
to control enzyme’s catalytic activities. Kinase and phosphatases
are commonly known enzymes that affect these modifications,
which result in shifting of conformational states of the binding
affinity to substrate.
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9. PHOSPHORYLATION
Phosphorylation is the addition of phosphate groups to proteins,
which is the most frequent regulatory modification mechanism in our
cells. This process takes place in prokaryotic and eukaryotic cells (in
this type of cells, a third or a half of the proteins experience
phosphorylation). Because of its frequency, phosphorylation has a lot
of importance in regulatory pathways in cells.
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10. PRETEOLYSIS
Some enzymes need to go through a maturation process to be
activated. A precursor (inactive state, better known as zymogen) is
first synthesized, and then, by cutting some specific peptide bonds
(enzymatic catalysis by hydrolytic selective split), its 3D
conformation is highly modified into a catalytic functional status,
obtaining the active enzyme.
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11. Proteolysis is irreversible, which implies the need of a process of
enzyme deactivation. Specific inhibitors, analogous to the
substrate, will strongly join the enzyme, blocking the substrate to
join the enzyme. This union may last for months.
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12. THANK YOU…. 
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