a seminar on proteins

1. Presented by:- Dr K. ABHILASHA
Moderated by:- Dr HARINI
DEPARTMENT OF
PERIODONTICS

2. INTRODUCTION
SOURCES OF PROTEINS
FUNCTIONS
STRUCTURE AND CHEMISTRY OF PROTEINS
CLASSIFICATION
METABOLISM
DEFICIENCY
ROLE ON PERIODONTAL TISSUES
ADVANCED APPROACHES WITH PROTEINS
CONCLUSION
REFERENCES

3. Proteins are the most abundant organic molecules of the
living system which occur in every part of the cell and
constitute about 50% of the cellular dry weight.
The term protein is derived from a Greek word ‘proteios’
meaning holding the first place.
First described by MULDER and BERZELIUS in 1838
First protein to be sequenced was INSULIN by
FREDRICK SANGER in 1958
First protein structure to be solved were HEMOGLOBIN
and MYOGLOBIN by MAX PERUTZ and SIR J.C.
KENDREW in 1958, respectively.

4. Around 68 percent of people have lower protein content in
their body than adequate and 71 percent of the people
have poor muscle health,"
• Survey report by IPSOS, December 2018
84 per cent of Indian vegetarian diet and 65
per cent of non-vegetarian diets are protein
deficient.
• Research study by IMRB(Indian Market Research Bureau,
2017)
As per the Recommended Dietary Allowance (RDA) given by
Indian Council of Medical Research (ICMR) for Indians, 0.8 to
1 gm protein per kg body weight per day is the requirement of
a normal, sedentary person without any disease.

6. • The quality of a dietary protein
is a measure of its ability to
provide the essential amino
acids required for tissue
maintenance.
• Most government agencies
have adopted the Protein
Digestibility–Corrected Amino
Acid Score (PDCAAS) as a
standard by which protein
quality is evaluated.

7. • Responsible for structure and
strength of body
• Example- collagen and elastin;
α-keratin
STRUCTURAL
FUNCTIONS
• Proteins performing dynamic functions
are appropriately regarded as the
working horses of cell.
• Such proteins act as enzymes,
hormones, blood clotting factors,
immunoglobulins,
DYNAMIC
FUNCTIONS

8. • Proteins predominantly consist of five major elements -
carbon, hydrogen, nitrogen, oxygen, sulphur.
• Proteins are polymers made up of monomers called
amino acids.
• There are 20 different amino acids.
• Amino acids can join up in any order and form an infinite
number of protein molecules.

9. • As many as 300 amino acids occur in nature.

11. -21ST amino acid- SELENOCYSTEINE
-22ND amino acid- PYRROLYSINE

12. Glycine
Alanine
Valine
Leucine
Isoleucine
Serine
Threonine
Cysteine
Methionine
Aspartic acid
Asparagine
Glutamic acid
Glutamine
Lysine
Arginine
Histidine
Phenylalanine
Tyrosine
Tryptophan
Proline
1.ALIPHATIC CHAIN
3.HYDROXYL
GROUP 6.SULFUR
CONTAINING
2.ACIDIC AMINO
ACIDS 5.BASIC AMINO
ACID
7.AROMATIC
AMINO ACID
4.IMINO ACIDS

13. NON
POLAR
AMINO
ACID
Alanine
Leucine
Isoleucine
Valine
Methionine
Phenylalani
ne
Tryptophan
Proline
POLAR
WITH NO
CHARGE
ON ‘R’
GROUP
Glycine
Serine
Threonine
Cysteine
Glutamine
Asparagine
Tyrosine
POLAR
WITH
NEGATIVE
CHARGE
Glutamic acid
Aspartic acid
POLAR
WITH
POSITIVE
CHARGE
Lysine
Arginine
Histidine

15. Glycogenic
amino acid
• Alanine,
• Aspartate,
• Glycine,
• Methionine,etc
Ketogenic amino
acid
• Leucine
• Lysine
Both glycogenic
and ketogenic
• Isoleucine,
• Phenylalanine,
• Tryptophan,
• Tyrosine

17. 1. Structural proteins : e.g Keratin of hair and nails,
collagen
2. Enzymes or catalytic proteins : e.g. Hexokinase,
pepsin.
3. Transport proteins : e.g. Hemoglobin, serum albumin.
4. Hormonal proteins : e.g. Insulin, growth hormone.
5. Contractile proteins : e.g. Actin, myosin.
6. Storage proteins : e.g. Ovalbumin, glutelin.
7. Genetic proteins : e.g. Nucleoproteins.
8. Defense proteins : e.g. Snake venoms, Immunoglobulins.
9. Receptor proteins for hormones, viruses.
A. FUNCTIONAL CLASSIFICATION

18. • From the nutritional point of view, proteins are classified
into 3 categories
1.COMPLETE PROTEINS
e.g. egg albumin, milk casein
2.PARTIALLY INCOMPLETE PROTEINS
e.g. wheat and rice protein (limiting lys,
thr)
3.INCOMPLETE PROTEINS
e.g. gelatin (lacks Trp), zein (lacks Trp,
Lys).

20. Protein metabolism denotes the various biochemical
processes responsible for the synthesis of protein
and amino acids, and the breakdown of proteins by
catabolism.
ABSORPTIO
N UTILISATION
DIGESTIO
N

21. • The intake of dietary protein is in the range of 50-100
g/day
- Dietary proteins are denatured on cooking & easily
digested
- About 30-100 g/day of endogenous protein is derived
from the digestive enzymes and worn out cells of the
digestive tract
• The digestion and absorption of proteins is very efficient
in healthy humans, hence very little protein (about 5-10
g/day) is lost through faeces.

23. • The absorption of amino acids occurs
mainly in the small intestine
 It is an energy requiring process
 Transport systems are carrier
mediated and/or ATP-Na+ dependent
symport systems
 5 different carriers for amino acids:
• Neutral amino acids (Ala, Val, Leu,
Met, Phe, Tyr, Ile)
• Basic amino acids (Lys, Arg)
• Imino acids
• Acidic amino acids (Asp, Glu)
• Beta amino acids ( beta Ala)

25. In intestines, kidney tubules and brain, the
absorption of neutral amino acids is effected
by the gamma glutamyl cycle.
Tripeptide glutathione (GSH) (gamma
glutamyl cysteinyl glycine) is essential for
Meister cycle.
• It reacts with the amino acid to form gamma
glutamyl amino acid.

27.  Immediately after birth, the small
intestine of infants can absorb
intact proteins and polypeptides
 The uptake of proteins occurs by a
process known as endocytosis or
pinocytosis
 The direct absorption of intact
proteins is very important for the
transfer of maternal
immunoglobulin's (γ-globulins) to
the offspring
 The intact proteins and
polypeptides are not absorbed by
the adult intestine

29. • The transfer of an amino (
NH2) group from an amino acid
to a keto acid is known as
transamination. catalysed by a
group of enzymes called
transaminases
 All transaminases require
pyridoxal phosphate
 Important for the redistribution
of amino groups and production
of non-essential amino acids.

30. The removal of amino group from the amino
acids as NH3 is deamination.
Results in the liberation of ammonia for urea
synthesis
Deamination may be either oxidative or non-
oxidative.

31. I. Oxidative deamination
 Oxidative deamination is the liberation of free ammonia
from the amino group of amino acids coupled with
oxidation.
 This takes place mostly in liver and kidney.
•A. ROLE OF GLUTAMATE DEHYDROGENASE

32. L-Amino acid oxidase and D-
amino acid oxidase are
flavoproteins, possessing
FMN and FAD, respectively.
They act on the
corresponding amino acids
(L or D) to produce-keto
acids and NH3.
In this reaction, oxygen is
reduced to H2O2, which is
later decomposed by
catalase.

33. • Amino acids can be deaminated to liberate NH3
without undergoing oxidation.
(a) Amino acid dehydrases
(b) Amino acid desulfhydrases
(c) Deamination of histidine

34. At the physiological pH, ammonia exists as
ammonium (NH+4) ion.
Even a marginal elevation in the blood
ammonia concentration is harmful to the
brain. Ammonia, when it accumulates in the
body, results in slurring of speech and
blurring of the vision and causes tremors. It
may lead to coma and, finally, death, if not
corrected.

35. o Urea is the end product of protein metabolism
o Urea is synthesized in liver and transported to kidneys for
excretion in urine

36. 2. Metabolic defects
1. Clinically, Blood urea estimation is widely used as a
screening test for the evaluation of kidney (renal)
function.

37. • Disorders caused by a protein-deficient diet
occurring shortly after birth and lasting a relatively
long time
• In such diets there is generally an overall calorie
deficiency. If life continues for a prolonged period under
these conditions it is observed that the rate of growth
slows down and the tissues are late in attaining
biochemical maturity. (McCance, 1960, 1968)
• A diet that is deficient in calories prevents the DNA
replication process but allows cell volume to increase,
whereas a diet that is low in protein but adequate in
calories does not hamper cell division although the cells
remain small. (Cheek ,1968)

38. • Disorders caused by a protein-deficient diet
occurring suddenly after a period of normal
diet
• Protein and calorie deficiencies are considered
under a single general heading ( Kerpel-Fronius,
1957)
• Two clinical forms of the protein deficient state,
pure kwashiorkor and marasmus

39. • Pure kwashiorkor or 'sugar baby' is the clinical
condition attained by children, and particularly
babies, when they are fed with a diet that is rich in
calories, mainly of carbohydrate origin, and very
poor or completely lacking in proteins. (Jelliffe,
Bras & Stuart, 1954)
• Kwashiorkor is most common in places where there
is famine, short food supply and low education
levels, and thus a lack of knowledge about proper
nutrition.
• In very poor countries, it is often concurrent with
natural disasters, drought and political unrest.

40. - WHO ARE THOSE PEOPLE AFFECTED BY THIS
DEFICIENCY???
- 1. CHILDREN- Protein malnutrition in children is typically
a sign of abuse or neglect
- 2 .ELDERLY- Protein deficiency may also occur among
the elderly in nursing homes, an estimated 20 percent of
whom experience undernutrition
- 3. Individuals with conditions that cause malabsorption of
nutrients, such as celiac disease, Crohn's disease and
tropical sprue, may become deficient in protein

41.  Abdominal swelling, distension or
bloating
 Diarrhoea
 Enlarged liver
 Fatigue
 Frequent infections
 Generalized swelling
 Hair and nail changes, including brittle,
reddish hair and ridged nails that are thin
and soft
 Skin changes, including pigment loss,
red or purple patches, peeling, cracking,
skin sloughing, and the development of
sores
 Slowed growth leading to short stature
 Weight loss

42. Common treatments for kwashiorkor include:
• Gradual increases in dietary calories from
carbohydrates, sugars and fats
• Intravenous fluids to correct fluid and
electrolyte imbalances
• Lactase to assist in digestion of dairy products
• Vitamin and mineral supplements to treat
deficiencies
• Antibiotics to treat infections

43. • •Anemia (low red blood cell count)
• •Coma
• •Frequent infections
• •Intellectual disability
• •Physical disability
• •Poor wound healing
• •Shock
• •Short stature
• •Skin pigmentation changes
• •Fatty liver

44.  To prevent
kwashiorkor, make
sure the diet has
enough carbohydrates,
fat (at least 10 percent
of total calories), and
protein (12 percent of
total calories).
 Food rich in proteins,
such as meat, fish,
dairy products, eggs,
soya, and beans to be
consumed adequately.

45. • Marasmus is a condition of general undernourishment
which occurs when the diet is reduced in calories but the
ratio of proteins to other nutrients remains the same
(Kerpel-Fronius, 1957).
• Marasmus is a state of extreme emaciation; it is the
outcome of prolonged negative energy balance.
• Not only have the body's fat reserves been exhausted,
but there is wastage of muscle as well, and as the
condition progresses there is loss of protein from the
heart, liver, and kidneys.
• Marasmus can occur in both adults and children, and
occurs in vulnerable groups of all populations

46. 1. Poor feeding habits
2. A physical defect e.g. cleft lip or cleft palate or
cardiac abnormalities, which prevent the infant
from taking an adequate diet
3. Diseases, which interfere with the assimilation
of food e.g. cystic fibrosis.
4. Infections, which produce anorexia.
5.Loss of food through vomiting and diarrhea.
6.Emotional problems e.g. disturbed motherchild
relationship.

47. • Growth retardation:- Weight is less than 60% of
expected for age and sex.
• Loss of Subcutaneous Fat from:
-- The abdominal wall leading to loss of skin
elasticity
-- The limbs- the skin becomes wrinkled and
hanging into longitudinal folds.
-- The buccinators pad of fat is the last to disappear.
This leads to hollowing the cheeks, which leads to
triangle face and an appearance resembling the old
man

48. • Marked Wasting of
Muscles:
• Psychic Changes
• Chronic diarrhoea with or
without vomiting
• Associated deficiencies of
iron, vitamin A and D.
• Hypothermia due to loss
of subcutaneous fat

50. • Deficiencies of protein C and protein S are inherited
conditions that cause abnormal blood clotting
• Deficiency of protein C occurs in about 1 out of 300
people.
• Deficiency of protein S affects 1 in 20,000 people.

51. • Symptoms for these deficiencies include redness, pain,
tenderness or swelling in the affected area.
• People with these protein deficiencies need to be careful
about activities that increase risk of blood clots, such as
prolonged sitting, bed rest, and long-time travel in cars
and airplanes.
• Research by A. Hooda published in the "Annals of
Indian Academy of Neurology" in 2009 discovered that
protein S deficiency causes ischemic stroke.

52. • Cachexia is a condition that involves protein deficiency,
depletion of skeletal muscle and an increased rate of
protein degradation
D.P. Kotler published in the "Annals of Internal
Medicine" in 2000.

53. • Cachexia causes weight loss and mortality and is
associated with cancer, AIDS, chronic kidney failure,
heart disease, chronic obstructive pulmonary disease
and rheumatoid arthritis
J.E. Morley in the "American Journal of Clinical
Nutrition.“

55. - The epithelium of the gingival crevice or pocket adheres
to the tooth surface by physicochemical forces mediated
by the proteins and glycoproteins in the gingival fluid.
Protein
deficiency
-Degeneration of the
connective tissue of
gingiva and
periodontal ligament
-Impaired deposition
of cementum
-Delayed wound
healing (Riar et al
1964)
-Osteoporosis of
alveolar bone
-Delayed wound healing
-Atrophy of tongue
epithelium
-Retardation in the
deposition of cementum
(Stahl et al 1958)

56. Rapid rate of turn over of epithelial cells of gingival sulcus
indicates the need of continuous synthesis of DNA, RNA
and tissue protein.
This indicates that sulcular epithelium has high
requirement of such nutrients as folic acid and protein
which are involved in cell formation.
At the base of the sulcular epithelium is a narrow
basement membrane made up of collagen
Since collagen is the major component of basement
membrane and ascorbic acid and zinc are important for
collagen synthesis.
This membrane act as a barrier for entrance of toxic
material.
Esaki M, Morita M, Akhter R, Akino K, Honda O. Relationship between folic acid
intake and gingival health in non-smoking adults in Japan. Oral Dis 2009:16: 96–
101.

57. • THERAPEUTIC PROTEIN THERAPY
• “Proteins which are engineered in the laboratory for
pharmaceutical use are referred to as therapeutic
proteins.
• Proteins which are absent or low in individuals with an
illness such as Cancer, are artificially synthesized on
large scale through genetically modified host cells and
delivered.
• This therapeutic approach in treating diseases using
proteins and peptides is termed protein therapeutics
therapy
• Introduced in 1920’s, Human insulin is considered to be
the first therapeutic protein

62.  Proteins mediate virtually every process that takes place
in a cell exhibiting an almost endless diversity of
functions.
 They are the most abundant biological macromolecules,
occurring in all cells and all parts of cells.
 As the arbiters of molecular function, proteins are the
most important final products of the information
pathways and hence share a major part of the diet.

63.  TEXTBOOK OF BIOCHEMISTRY BY SATYANARAYANA
 HARPER’S ILLUSTRATED BIOCHEMISTRY, 28TH EDITION
 TEXTBOOK OF CLINICAL PERIODONTOLOGY, CARRANZA 10TH EDITION
 LEHINGER PRINCIPLES OF BIOCHEMISTRY 10TH EDITION, DAVID NELSON
 Bell CL, Lee AS, Tamura BK. Malnutrition in the nursing home. Current Opinion
in Clinical Nutrition & Metabolic Care. 2015 Jan 1;18(1):17-23.
 Nevins M, Giannobile WV, McGuire MK, Kao RT, Mellonig JT, Hinrichs JE,
McAllister BS, Murphy KS, McClain PK, Nevins ML, Paquette DW.
Platelet‐derived growth factor stimulates bone fill and rate of attachment level
gain: Results of a large multicenter randomized controlled trial. Journal of
periodontology. 2005 Dec 1;76(12):2205-15.
 Esaki M, Morita M, Akhter R, Akino K, Honda O. Relationship between folic acid
intake and gingival health in non-smoking adults in Japan. Oral Dis 2009:16: 96–
101.