The document discusses post-translational modifications (PTM) of proteins. It defines PTM as the chemical modification of proteins after translation, including phosphorylation, acetylation, methylation, glycocylation, and other types of modifications. These modifications are important as they increase protein diversity and regulate functions like activity, localization, and interactions. The document also describes techniques for detecting PTM, including mass spectrometry and blotting.

1. Muhammad Kamil Khan
Microbiologist

2.  Introduction to PTM
 Importance of PTM
 Types of PTM
 Detection of PTM

3.  The chemical modification of protein during or after
translation by covalent or enzymatic activity called
post translational modification of protein.
 It can be occur on the amino acid side chains or at the
protein's C- or N- termini.
 In human it will increase the diversity and accuracy of
protein.

5.  Phosphorylation
 Acetylation
 Hydroxylation
 Methylation
 Glycocylation
 Lipidation
 Ubiqutination or protein
degradation or proteolysis
 Deamidation
 Sulfation
 Carboxylation
 Biotinylation
 Nitrosylation
 Protein splicing
 Protein folding

6.  Addition of one or more phosphate group to protein.
 Helps to regulate biological activity of protein.
 In animal cells serine, tyrosine and thereonine are the
amino acid that are subjected to Phosphorylation.
 Play a key role in cell cycle growth apoptosis and signal
transduction pathway.

8.  The addition of an acetyl group to nitrogen or usually at
the N-terminus of protein
 Regulates transcriptional factors, effectors proteins
molecular chaperon and cytoskeleton protein.
 Methoinine amino peptidase is an enzyme responsible for
N-terminal Acetylation.

10.  The biological process in which the hydroxyl group is
added to protein amino acid in which CH group is
converted into COH group and the amino acid is called
hydoxylated amino acid which involved the regulation of
some important factors called transcription factors.
 Can add hydroxyl group to proline and lysine.

12.  The addition of methyl group to carbon and then transfer
from carbon to nitrogen or oxygen of protein amino acid
chain by methyl transferases and s-adenosine Methoinine
is called Methylation
 The SAM usually add methyl group at lysine or arginine
 Increase the hydrophobicity of protein and can neutralize
a negative amino acid charge when bound to carboxylic
acid

14.  The addition of carbohydrate molecule i.e. saccharide to a
protein and modified it to glycoprotein
 The protein in cell membrane and secreted from the cell
having carbohydrate chain attached to amide nitrogen of
asparagines or hydroxyl group of serine.
 Two types i.e. N-glycocylation occurs in ER and O
glycocylation occurs in Golgi complex.
 It effect on protein folding, conformation, distribution,
stability and activity.

16.  Attachment or addition of lipid group i.e. fatty acid
covalently to a protein
 Helps in cellular localization and targeting signals
 Lipidation can be further subdivided into prenylation, N-
myristoylation and palmitoylation.

18.  Deamidation is the removal or conversion of asparagine
or glutamine residue to another functional group.
Asparagine is converted to aspartic acid or isoaspartic
acid, while glutamine is converted to glutamic acid or
pyroglutamic acid. This modification can change the
protein structure, stability, and function.

20.  The addition of sulphate molecule for protein modification
occur at tyrosine by tyrosylproteinsulfotransferases
enzymes
 Sulfation is involved in a variety of biological processes,
including detoxification, hormone regulation, molecular
recognition, cell signaling, and viral entry into cells.

22.  The chemical reaction in which the addition of
carboxyl group to protein occur at glutamate amino
acid by treating a substrate with CO2
 The reaction is catalyzed by Ribulose-1,5-
bisphosphate carboxylase/oxygenase

24.  Biotin is a coenzyme essential to all life forms.
 Most organisms have only one enzyme for attachment of
biotin to other proteins and the sequences of these
proteins and their substrate proteins are strongly
conserved throughout nature.

26.  The addition of nitric oxide group to amino acid chain or
protein
 Nitric oxide (NO) plays an important role in the
regulation of cardiovascular function.

28.  There are several chemical and biological technique for
the detection of PTM that whether the modification in
protein occur completely or not.
 Theses method are:
1. Mass spectrometry.
2. Florescent staining of two dimensional gels.
3. Immune system activation.
4. Western and eastern blotting.

29.  Important for the cell to live and progress
 The protein become mature and can regulate the
protein function
 Due to glycocylation in PTM it will play a key role in
immune regulation e.g. development, survival and
reactivity of T cell
 The protein lipid modification in PTM have role in
protein –membrane interaction, protein trafficking
and enzyme activity

30.  Acetylation in PTM will regulate protein-protein
interaction and protein stability
 Help to utilize identical protein for different cellular
function in different cell
 Translocation of protein across biological membrane.
 Regulate activity, localization and interaction with other
cellular molecules i.e. nucleic acids, lipids and cofactors