Phosphorylation and Types of Phosphorylation.pdf

Phosphorylation is a complex process that's studied in Chemistry & Biology. We've made it easy for you to understand phosphorylation & types of Phosphorylation.

1. Phosphorylation and Types of Phosphorylation


Phosphorylation plays an important role in the areas of both Chemistry and
Biology. Let’s learn more about it an d how it works:
What Is Phosphorylation?
Phosphorylation can be defined as the chemical addition of a PO3 - (also
known as a phosphoryl group) to an organic molecule. There is a process
that is the complete opposite of the phosphorylation process and it is known
as dephosphorylation. Dephosphorylation is the removal of a phosphoryl
group (PO3 -) from an organic molecule chemically. Both processes
(phosphorylation and dephosphorylation) are performed by enzymes such as
kinases and phosphotransferases, etc. The phosphorylation reaction is of

2. paramount importance in the fields of molecular biology and biochemistry
since it is a vital reaction in energy storage and release, protein and enzyme
function, and sugar metabolism.
Why Is Phosphorylation So important?
Well, phosphorylation sits at the center of all important reactions happening
in the cell. It plays an important critical regulatory role in our cells and
performs the following roles:
• Phosphorylation maintains the state of homeostasis by regulating
chemical reactions that require energy.
• It is vital for glycolysis.
• It is also used for protein-protein interaction.
• Moreover, it is used in protein degradation.
• Phosphorylation also regulates the inhibition of enzymes.
What Are The Types Of Phosphorylation?
There are three major types of phosphorylation. They are oxidative
phosphorylation, glucose phosphorylation, and protein phosphorylation.
Let’s dive straight into them and find out what they are:
1. Oxidative Phosphorylation
Oxidative phosphorylation is th e process by which the cells store and release
chemical energy in the body. In a eukaryotic cell, oxidative phosphorylation
occurs in the mitochondria which is the powerhouse of the cell. The
reactions occurring in the electron transport chain’s chemiosmos is are

3. actively involved in oxidative phosphorylation. In a nutshell, the redox
reaction passes electrons from proteins via the electron transport chain
present in mitochondria’s inner membrane. This releases energy and that
energy is used to make ATP in c hemiosmosis.
During this procedure, the FADH2 & NADH molecules deliver electrons to the
electron transport chain where they move from higher to lower energy and
release energy which is partly used to pump hydrogen ions (H+) to create an
electrochemical gradient. Lastly, the electrons are transferred to oxygen to
bond with H+ for the formation of water. At the dephosphorylation of ATP,
the cleaved phosphate group releases energy so the cell can use it again.
Other than Adenosine, other bases also undergo pho sphorylation such as
Guanosine.
2. Glucose Phosphorylation
Glucose also undergoes phosphorylation as the first step of its catabolism.
For instance, the very first step of glycolysis of D -glucose is the conversion
of D-glucose into D-glucose-6-phosphate. Glucose, on its own, is quite small
in size and can easily permeate cells. On the other hand, phosphorylation
creates a molecule large enough in size that it cannot readily permeate
tissues. So, the phosphorylation of glucose is important to regulate blood
glucose concentration which is related to glycogen formation and thus
affects cardiac growth.
3. Protein Phosphorylation
Lastly, we have Protein Phosphorylation which was not studied until the
1930s, however, in 1906, Phoebus Levene at the Rockefeller Institute for
Medical Research was able to identify Phosvitin which is a phosphorylated
protein.

4. So, what is protein phosphorylation? It is the process of the addition of a
phosphoryl group to an amino acid which is normally serine, however, the
process can also occur on histidine (in prokaryotes) and threonine and
tyrosine (in eukaryotes). In this procedure, a phosphate group undergoes a
reaction with a hydroxyl (-OH) group of a tyrosine, threonine, or serine side
chain where the enzyme protein kinase creates a covalent bond between a
phosphate group and the amino acid. It occurs differently in prokaryotes and
eukaryotes. The Posttranslational modifications (PTM) are the best -studied
types of phosphorylation in which proteins are phosphorylated after they
are translated from an RNA template.
Another amazing example of protein phos phorylation is histones
phosphorylation. It occurs in eukaryotes where it modifies the chromatin
structure and changes its DNA -protein and protein-protein interactions. This
process normally occurs when the DNA gets damaged and it results in the
space around the broken DNA opening up so the repair mechanisms can get
to their work.
So, there you have a complete breakdown of phosphorylation and its three
major types. Best of luck!