proteins and amino acids

1. Presented by:
Faiza Azhar
M.Phil. (Pharmaceutical Chemistry)
Amino acids and Proteins

2. Protein
 Protein: From the Greek word “PROTEIOS”
which means "to be first (in rank or influence)"
 Why are proteins important to us:
o Proteins make up about 15% of the mass of
the average person
o Enzyme – acts as a biological catalyst
o Storage and transport – Haemoglobin
o Antibodies
o Hormones – Insulin

3. Definition:
 Proteins are organic compounds with a high
molecular weight formed of carbon, oxygen,
hydrogen and nitrogen and may also contain
sulfur, phosphorus coloring non-protein organic
groups and metal ions
 They are polymers formed of subunits called
amino acids linked together by peptide linkage

4. Best Sources of Protein:
 Proteins are abundant in
o Dairy foods
o Meats
o Poultry
o Meat alternatives such as dried beans, peanut
butter, nuts, and soy
 3 oz. serving of cooked meat, poultry, or fish
o Provides 21–25 grams of protein
o About 7 g/oz
o Adequate amount for one meal

5. Amino Acids:
 Amino acids are organic acids that contain NH2
group.
 They are the structural units of proteins and are
obtained from them by hydrolysis.
 The general formula of any amino acid is as
follows:
H2N CH C
R
OH
O

6. Classification of Amino acids
Amino Acids
Metabolic classification
Biological classification
Chemical classification
Basic Amino Acids
Acidic Amino Acids
Neutral Amino acids
Non-essential Amino
acids
Essential Amino acids
Mixed Amino acids
Ketogenic Amino acids
Glucogenic Amino
acids

7. A) Neutral amino acids:
 They contain one amino group and one
carboxyl group. They have 5 types:
1-Aliphatic amino acids: e.g.,
H2N CH C
H
OH
O
H2N CH C
CH3
OH
O
H2N CH C
CH
OH
O
CH3
CH3
H2N CH C
CH2
OH
O
CH CH3
CH3
H2N CH C
CH
OH
O
CH3
CH2
CH3
Alanine
Leucine Isoleucine
Valine
Glycine

8. 2. Hydroxy amino acids:
Hydroxy amino acids: e.g.
serine, threonine.
H2N CH C
CH2
OH
O
OH
H2N CH C
CH
OH
O
OH
CH3
Threonine
Serine

9. 3. Aromatic amino acids:
3. Aromatic amino acids: e.g.,
phenylalanine and tyrosine .
 Tyrosine is synthesized from phenyl alanine and
both give triiodothyronine and thyroxin,
adrenaline and noradrenaline
 Melanin pigment and cresol, phenol in the body,
e.g.
H2N CH C
CH2
OH
O
H2N CH C
CH2
OH
O
OH
Phenyl alanine
Tyrosine

10. 4-Sulfur-containing amino
acids:
Cysteine and methionine are two important
Sulfur containing amino acids
H2N CH C
CH2
OH
O
SH
H2N CH C
CH2
OH
O
CH2
S
CH3
Cysteine
Methionine

11. 5-Heterocyclic amino acids:
5-Heterocyclic amino acids: e.g.,
 Histidine gives histamine a very important
inflammatory mediator.
 Proline gives hydroxyproline that is
essential for collagen cross-linking.
 Tryptophan gives nicotinic acid, melatonin
H2N CH C
CH2
OH
O
N
NH
H2N CH C
CH2
OH
O
HN
HN
C OH
O
Histidine Tryptophan
Proline

12. B) Acidic amino acids:
 They contain 2 carboxyl groups and one
amino group, e.g., glutamic acid and
asparatic acid.
 These acidic amino acids can occur in the
tissue in the form of amides, e.g., glutamic
acid  glutamine and asparatic acid 
asparagine
H2N CH C
CH2
OH
O
CH2
C
OH
O
H2N CH C
CH2
OH
O
CH2
C
NH2
O amide
group
Glutamine
Glutamic acid
H2N CH C
CH2
OH
O
C
OH
O
H2N CH C
CH2
OH
O
C
NH2
O
Asparagine
amide
group
Asparatic acid

13. Basic amino Acids:
 Lysine: Contain two amino (-NH2) groups and
one carboxylic (-COOH) group.
H2N CH C
CH2
OH
O
CH2
CH2
H2C
NH2
Lysine

14. II-Metabolic classification:
 Amino acids may be classified into
A -Glucogenic amino acids: i.e., those which can
be converted into glucose
B -Ketogenic amino acids: i.e., those which can be
converted into ketone bodies
C -Mixed amino acids: i.e., those which can be
converted into both glucose and ketone bodies.

15. Ketogenic Ketogenic &
glucogenic
Glucogenic
Leucine Lysine Rest of amino
acids
Isoleucine
Tyrosine
Tryptophan
Phenyl alanine

16. III-Biological or Nutritional
Classification:
 Some amino acids can not be synthesized
inside the body
 If these amino acids are not taken in diet they
will affect the growth and the health. Thus,
amino acids may be classified into:

17. A- Essential amino acids:
 These are amino acids that can not be
synthesized in the human body and should be
taken in the diet, otherwise their deficiency will
lead to a nutrition deficiency disease that affect
both growth and health.

18. Conti……
Eight amino acids are generally regarded as
essential for humans: tryptophan, lysine,
methionine, phenylalanine, threonine, valine,
leucine, isoleucine
Two others, histidine and arginine are essential
only in children. A good mnemonic device for
remembering these is "Private Tim Hall",
abbreviated as:
PVT TIM HALL:
Phenylalanine, Valine, Tryptophan
Threonine, Isoleucine, Methionine
Histidine, Arginine, Lysine, Leucine

19. B- Non essential amino acids:
 The rest of amino acids can be synthesized
inside the human body and their deficiency in
diet does not affect the growth or the health
 Or derived from essential amino acids
 Alanine, Asparagine, Glutamate, Glutamine,
Cysteine, Aspartate, Glycine, Tyrosine, Proline
and Serine

20. C. Conditional Amino Acid
 Can not be synthesized due to illness or lack of
necessary precursors
 Premature infants lack sufficient enzymes
needed to create arginine

21. Classification of Proteins
Proteins
Based on
Source
Based on
Function
Based on
Structure
Based on
Solubility
Based on
composition
Fibrous
Proteins
Globular
Proteins
Membranous
proteins
Microbial
Source
Plant
Source
Animal
Source
Insoluble
Proteins
Soluble
Proteins
Conjugated
Proteins
Simple
Proteins
Structural
Proteins
Transport
Proteins
Hormonal
Proteins
Antibodies
Enzymes

22. A. Based on Structure
• Fibrous Proteins: These proteins have a long,
elongated shape and are often involved in
structural roles.
• Examples: Collagen, keratin, and elastin.
• Globular Proteins: These proteins have a more
spherical shape and are often involved in
functional roles.
• Examples: Enzymes, antibodies, and hemoglobin.
• Membrane Proteins: These proteins are
associated with cell membranes and can span the
lipid bilayer.
• Examples: Integral membrane proteins and
peripheral membrane proteins

23. B. Based on Function
• Enzymes: Proteins that catalyze biochemical
reactions.
• Examples: Amylase, catalase, and DNA polymerase.
• Structural Proteins: Proteins that provide
support and structure to cells and tissues.
• Examples: Collagen, actin, and tubulin.
• Transport Proteins: Proteins involved in the
movement of substances across cell membranes
or within the bloodstream.
• Examples: Hemoglobin, albumin, and ion channels.
• Hormonal Proteins: Proteins that act as
signaling molecules regulating physiological
processes.
• Examples: Insulin, growth hormone, and adrenaline.

24. • Antibodies (Immunoglobulins): Proteins
involved in the immune response, recognizing
and neutralizing pathogens.
• Examples: IgG, IgA, and IgM.
• Receptor Proteins: Proteins that bind to
specific signaling molecules, initiating a
cellular response.
• Examples: G protein-coupled receptors (GPCRs)
and receptor tyrosine kinases (RTKs).

25. C. Based on Source
• Animal Proteins: Proteins derived from
animal sources.
• Examples: Meat, eggs, and dairy products.
• Plant Proteins: Proteins derived from plant
sources.
• Examples: Legumes, grains, and vegetables.
• Microbial Proteins: Proteins produced by
microorganisms, often used in biotechnology.
• Examples: Recombinant proteins produced in
bacteria or yeast.

26. D. Based on solubility
• Soluble Proteins: Proteins that are readily
soluble in water.
• Examples: Albumin, enzymes in the cytoplasm.
• Insoluble Proteins: Proteins that have limited
solubility in water.
• Examples: Collagen, keratin.

27. E. Based on composition
• Simple Proteins: Proteins composed of only
amino acids.
• Examples: Albumins, globulins.
• Conjugated Proteins: Proteins combined with
non-protein components (prosthetic groups).
• Examples: Hemoglobin (contains heme),
lipoproteins.

28. Biological Importance of
Proteins
 Structural Support: Proteins provide structural support to
cells and tissues. For example, collagen is a fibrous
protein that forms the structural framework of connective
tissues in animals, providing strength and elasticity to skin,
bones, tendons, and other tissues.
 Enzymatic Catalysis: Proteins function as enzymes,
catalyzing biochemical reactions by facilitating and
accelerating chemical reactions. Enzymes are crucial for
processes such as digestion, energy production, and
synthesis of essential molecules.
 Transportation: Proteins are involved in the
transportation of various substances within organisms.
Hemoglobin, for instance, is a protein that transports
oxygen in the blood, while membrane transport proteins
facilitate the movement of ions and molecules across cell
membranes.

29. Biological Importance of
Proteins
 Immune Response: Antibodies, which are specialized proteins,
play a critical role in the immune system by recognizing and
neutralizing foreign invaders such as bacteria, viruses, and
other pathogens.
 Hormones: Some proteins act as hormones, signaling
molecules that regulate and coordinate various physiological
processes. For example, insulin is a protein hormone that
regulates blood glucose levels.
 Cellular Communication: Signaling proteins, like receptors on
cell membranes, transmit signals and facilitate communication
between cells. These proteins are crucial for maintaining
homeostasis and coordinating responses to external stimuli.
 Muscle Contraction: Proteins such as actin and myosin are
essential for muscle contraction. The interaction between these

30. Biological Importance of
Proteins
 Storage and Transport of Molecules: Proteins can serve as storage
molecules, storing nutrients or ions for later use. Ferritin, for instance,
stores iron in a non-toxic form. Additionally, proteins like albumin
transport various molecules in the blood.
 DNA Replication and Repair: Enzymes involved in DNA replication,
repair, and recombination are proteins. These processes are
fundamental for the accurate transmission of genetic information
during cell division.
 Metabolic Regulation: Proteins are involved in the regulation of
metabolic pathways, controlling the rates of various biochemical
reactions and ensuring the efficient use of energy and resources.
 Cytoskeleton and Cell Shape: The cytoskeleton, made up of protein
filaments such as microtubules and microfilaments, provides
structural support to cells and is involved in maintaining cell shape

31. Pharmaceutical Importance of
Proteins
 Drug Targets: Proteins are common targets for drug
development. Many drugs act by interacting with specific
proteins, either inhibiting or enhancing their functions.
Enzymes, receptors, and other proteins involved in disease
pathways are often targeted to modulate biological
processes and treat various conditions.
 Enzyme Inhibitors: Many drugs function as enzyme
inhibitors, targeting specific proteins to block or modulate
enzymatic activity. This is particularly relevant in the
treatment of diseases where abnormal enzyme activity is a
contributing factor.
 Receptor Modulation: Drugs often target cell surface
receptors, which are proteins involved in signal
transduction. Modulating receptor activity can have
therapeutic effects, such as controlling pain, regulating
blood pressure, or influencing immune responses.

32. Pharmaceutical Importance of
Proteins
 Monoclonal Antibodies: Monoclonal antibodies are
proteins designed to target specific cells or proteins in the
body. They have been widely used in the treatment of
various diseases, including cancer, autoimmune disorders,
and infectious diseases.
 Vaccines: Vaccines often contain proteins or fragments of
proteins that trigger an immune response. This immune
response helps the body recognize and defend against
specific pathogens, providing immunity and preventing
diseases.
 Biopharmaceuticals: Many therapeutic proteins are
produced through biotechnological processes and used as
biopharmaceuticals. Examples include insulin for diabetes

33. Pharmaceutical Importance of
Proteins
 Diagnostic Proteins: Proteins are essential in
diagnostic medicine. Biomarker proteins, which are
indicative of specific diseases or conditions, are used for
diagnostic tests. For example, elevated levels of certain
proteins in the blood can be indicative of cardiac injury
or inflammation.
 Gene Therapy: Proteins are involved in gene therapy
approaches, where the goal is to introduce functional
genes into cells to correct genetic disorders. The
expressed proteins can compensate for or replace the
defective or missing proteins associated with the
disease.
 Protein Engineering: Advances in protein engineering
have allowed the development of proteins with improved

34. Pharmaceutical Importance of
Proteins
 Drug Delivery: Proteins can be utilized in drug
delivery systems to enhance the targeted delivery of
therapeutic agents. Protein carriers can improve the
pharmacokinetics and bioavailability of drugs,
allowing for more effective and selective treatment.
 Diagnostics and Imaging: Proteins are used in
diagnostic imaging techniques, such as positron
emission tomography (PET) and single-photon
emission computed tomography (SPECT), where
radiolabeled proteins can be employed to visualize
specific tissues or biomolecular processes.