Department of Biochemistry and Molecular Medicine,
UDS – SoM, Tamale Campus
SPS 105 :
BIOCHEMISTRY I
Lecturer :
Frederick Sarfo - Antwi
SMS 105:
BIOCHEMISTRY I
Lecture 2 :
Introduction to Protein
Lecturer :
Frederick Sarfo - Antwi
(BSc Biochem., MPhil. Biochem)
PhD Biochemistry Researcher, KNUST
Telephone : +233245766223
E mail : sarfoantwifrederick@yahoo.com
Course Objectives
At the end of the lesson, students should be
able to identify the biomolecules of living cells,
such as proteins (amino acids, peptides) and
disorders associated with these molecules.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Course Content
Protein Digestion
Amino Acids
Protein (biomolecule)
Protein deficiency
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Summary of Lesson
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Biomolecules of Living Cells
A biomolecule or biological molecule is a term
used to describe molecules present in
organisms that are essential to one or more
typically biological processes.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Biomolecules of Living Cells
Proteins (amino acids)
Carbohydrates
Lipids
Nucleic Acids
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Digestion of Dietary Proteins
The dietary proteins are hydrolysed to amino acids by
proteolytic enzymes, which can be easily absorbed.
Proteolytic enzymes responsible for degrading proteins
are produced by three different organs;
The stomach, pancreas and the small intestine.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Characteristics of Proteolytic enzymes
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Reactions of Proteolytic enzymes
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Role of Biochemistry in Pharmacy
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Biochemistry and Pharmacy
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Mechanisms of Transport
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Characteristics of Proteolytic enzymes
Endopeptidase acts inside the core of protein, forms small
peptide fragments
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Digestion of Protein starts in stomach
When proteins enters the stomach, it stimulates the secretion of
the hormone gastrin, from gastric mucosal cells.
This gastrin, in turn, stimulates the release of gastric juice, which
contains:
1. Hydrochloric acid (HCL)
2. Pepsinogen (zymogen)
3. Rennin (in infants)
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Characteristics of Proteolytic enzymes
Endopeptidase acts inside the core of protein, forms small
peptide fragments
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Pepsin Act on
Endopeptidase acts inside the core of protein, forms small
peptide fragments
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
From the Mouth to the Stomach
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
From the Stomach to the Small Intestine
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Mechanisms of Transport
Endocytosis – movement of substance or
molecule into the cell.
Exocytosis – movement of substance or
molecule outside the cell.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Characteristics of Proteolytic enzymes
Endopeptidase acts inside the core of protein, forms small
peptide fragments
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Mechanisms of Transport
Endocytosis – movement of substance or
molecule into the cell.
Exocytosis – movement of substance or
molecule outside the cell.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Overview of Protein Digestion
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Amino Acids
Amino acids are the monomers that
make up proteins.
Each amino acid has the same
fundamental structure.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Amino Acids
The chemical properties of the amino acids of
proteins determine the biological activity of the
protein. Proteins not only catalyse all (or most) of
the reactions in living cells, they control virtually
all cellular process.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
History of Amino Acids
Twenty (20) amino acids exist
Asparagine (1806) – asparagus
Threonine (1938)
Glutamate – wheat gluten
Tyrosine – tyros cheese
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Structure of Amino Acid
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Amino Acids share Common Structural Features
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Twenty Amino Acids
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Glycine Amino Acid
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Proline, a cyclic Amino acid
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Proline, a cyclic Amino acid
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Amino Acids can be Classified by R Group
Nonpolar, aliphatic R groups
Aromatic R groups
Polar, uncharged R groups
Positively charged R groups
Negatively charged R groups
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Nonpolar, aliphatic R groups
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Aromatic R groups
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Polar, uncharged R groups
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Cysteine (sulfhydryl group)
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Positively charged R groups
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Negatively charged R groups
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Negatively charged R groups
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Three letters abbreviation and One letter Symbol
Glycine Gly, G Lysine Lys, K
Alanine Ala, A Histidine His, H
Proline Pro, P Arginine Arg, R
Valine Val, V Aspartate Asp, D
Leucine Leu, L Glutamate Glu, E
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Three letters abbreviation and One letter Symbol
Serine Ser, S Isoleucine Ile, I
Threonine Thr, T Methionine Met, M
Cysteine Cys, C Phenylalanine Phe, F
Asparagine Asn, N Tyrosine Tyr, Y
Glutamine Gln, Q Tryptophan Trp, W
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Uncommon Amino Acids Also have Important
Functions
In addition to the 20 common amino acids,
proteins may contain residues created by
modification of common residues already
incorporated into a polypeptide
(Post-synthetic Modification)
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Uncommon Amino Acids Also have Important
Functions
4-hydroxyproline (found in collagen)
5-hydroxylysine (found in collagen)
6-N-Methyllysine (constituent of myosin)
Gamma carboxyglutamate (prothrombin)
Selenocysteine and Pyrrolysine
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Uncommon Amino Acids Structures
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Uncommon Amino Acids Structures
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Transiently Modification of Amino Acids
Phosphoryl group (Phosphorylation)
Methyl group (Methylation)
Acetyl group (Acetylation)
Adenylyl group (Adenylylation)
ADP-ribosyl (ADP-ribosylation)
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Phosphorylation of Aspartate into Phosphoserine
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Phosphorylation of Aspartate into Phosphoserine
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Peptides are Chains of Amino Acids
Two or more amino acid molecules are joined
through a peptide bond.
Such a linkage is formed by removal of water
(dehydration) from the carboxyl group of one amino
acid and the amino group of another amino acid.
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Condensation reaction of Amino Acids
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Hydrolysis reaction of Amino Acids
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Sequence of Amino Acids
Dipeptide Oligopeptide
Tripeptide Polypeptide
Tetrapeptide Protein (>10,000)
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Dipeptide
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Tripeptide
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Tripeptide
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Tetrapeptide
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Tetrapeptide
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Oligopeptide
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Polypeptide
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Protein
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Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Disorders Associated with Amino Acids
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Nomenclature of Peptides
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Nomenclature of Peptides
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Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Some Proteins Contain Chemical Groups other
Than Amino Acids
Simple Protein
Conjugated Protein
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Some Proteins Contain Chemical Groups other
Than Amino Acids
Simple Protein
Conjugated Protein
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Importance of Protein
Protein is an essential nutrient found in almost every part of
your body — including your bones, muscles, skin, hair, and nails.
Protein keeps your bones and muscles strong.
It makes up a molecule called hemoglobin, which carries
oxygen throughout your body.
It also makes up chemicals called enzymes, which cause the
many reactions that keep your organs working.
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Functions of Protein
They function as catalysts (e.g. hexokinase),
They transport and store other molecules (e.g.
haemoglobin and myoglobin),
They provide structural and mechanical support
(e.g. actin and myosin),
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Functions of Protein
They also provide immune protection (e.g.
immunoglobulins)
They control growth and differentiation.
Proteins also play a role in cell signalling as well
as cell adhesion
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency (1/3)
The term ‘protein deficiency’ represents a state of
relative or absolute deficiency of body proteins or one
or more of the essential amino acids.
Protein turnover’ reflects the balance of protein
degradation and synthesis.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency (1/4)
Protein deficiency, also called hypoproteinaemia, is
usually tied to overall low protein intake.
The condition affects about 1 billion people
worldwide but is rare in the US.
Overall, Americans tend to eat the recommended
amount of protein needed.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency (2/4)
The term ‘protein deficiency’ represents a state of
relative or absolute deficiency of body proteins or one
or more of the essential amino acids.
Protein turnover’ reflects the balance of protein
degradation and synthesis.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency (3/4)
More synthesis than breakdown indicates an anabolic state
that builds lean tissues.
More breakdown than synthesis indicates a catabolic state
that burns lean tissues.
NB: The quantitative relationship between circulating amino acid concentrations
and their rate of catabolism is not uniform, either between individuals or
between diets.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency (4/4)
Although the main cause of protein deficiency is a protein-
deficient diet, the disorder can commonly occur in a variety of
pathologic states.
The dietary treatment of protein deficiency depends on the cause
of the deficiency and must depend on a sound understanding of
the underlying disorder and the mainstay of treatment includes
balanced energy-protein and micronutrient supplementation.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Mechanisms of Transport
Endocytosis – movement of substance or
molecule into the cell.
Exocytosis – movement of substance or
molecule outside the cell.
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Signs and symptoms of protein deficiency
Edema
Fatty Liver
Skin, Hair and Nail Problems
Loss of Muscle Mass
Greater Risk of Bone Fractures
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Causes of Protein Deficiency (Hypoproteinemia)
Inadequate protein
Malabsorption
Liver damage
Kidney damage
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Effects of Protein Deficiency
Edema
Fatty Liver
Anemia
Skin, Hair and Nail Problems
Loss of Muscle Mass
Greater Risk of Bone Fractures
Increased Severity of Infections
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Protein Deficiency in Pregnancy
Kwashiorkor
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Causes of Protein Deficiency (Hypoproteinemia)
Inadequate protein
Malabsorption
Liver damage
Kidney damage
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Diseases of Protein Deficiency
Kwashiorkor
Marasmus
Cachexia
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Kwashiorkor
Kwashiorkor
Marasmus
Cachexia
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Cachexia
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Treatment for Protein Deficiency (1/2)
Increase protein in diet
Antibiotics or anti-parasitic drugs to treat infections
Vitamin and mineral supplements
Gluten-free diet to treat damage to your intestines from
celiac disease
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Treatment for Protein Deficiency (2/2)
Steroids, immune system suppressors, and other drugs
to bring down inflammation in your intestines
Medications or surgery to treat liver damage
Dialysis or a kidney transplant to treat kidney disease
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Structure of Protein
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Disorders Associated with Proteins
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Alzheimer’s Disease
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
Structure of Protein
Department of Biochemistry and Molecular Medicine, UDS – SoM, Tamale Campus
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