PROTEIN
Dept. of Medical Nutrition
Medicine School Padjadjaran University
PROTEIN
 A compound
of C,H,O and N molecules
that bind in a fashion way to form amino
acids
 Amino acids bind to each other to
form protein
 Amino acids bound --> peptide bound
 Protein Nitrogen (PN)
 Non Protein Nitrogen (NPN)
Classification of amino acid
1. Essential amino acid (EAA)

Could not synthesized by the body
 Should get from outside the body (Exogen)
 Adults need 8 essential amino acids which
are : isoleusin, leusin, lysin, phenilalanin,
methionin, threonin, tryptophan, valin
 Children need histidin & arginin adjacent to
the 8 essential amino acids mentioned above
Essential amino acids
1. Isoleucine
2. Leucine
3. Lysin
4. Methionine
5. Phenylalanine
6. Threonine
7. Tryptophan
8. Valin
9. Histidin
10.Arginin
2. Non essential amino acids
(Non EAA)
 Synthesized
by the body from nitrogen
and amino acid carbon chain
 Non essential amino acids are important
to the body but not essential from food
(exogen)
Non essential amino acids
1. Glycine
2. Glutamic acid
3. Arginine
4. Aspartic acid
5. Proline
6. Alanine
7. Serine
8. Tyrosine
9. Cystein
10. Asparagine
11. Glutamine
12. Hydroxy glut acid
13. Hydroxy lysine
14. Hydroxy proline
15. Thyroxine
16. Norleucine
17. Cystine
18. Taurine
19. Carnitine
Protein classified as follow :
1. Complete Protein
- High biologic value (HBV)
- Contain all EAA
- Sufficient quantum of EAA
- Meet the body needs
- Able to support growth and to maintain
body tissue
E.g. : egg, meat, poultry, fish & milk
2. Half complete protein :
- Contain all of EAA
- Insufficient quantum of EAA
- Able to maintain adult health
- Unable to support children growth
E.g. : rice, wheat, tapioca
3. Incomplete Protein :
- Contain fewer EAA
- Lesser EAA quantum
- Inadequate to maintain health
- Unable to support growth
E.g. : gelatin, zein on corn
Role of Protein
Provide amino acids for :
 Growth and development
 Maintain the body tissues
 Produce energy
 Protein synthesis
Protein food sources
Protein
in the food should
provide adequate quality and
quantity that meet the body
need.
Animal Protein
 High
biological value
 Complete protein
 Equivalent to body protein composition
 Digestible and well absorb by the
intestine
Plant Protein
 Within
the plants, protein covered by
cellulose wall
 Plant proteins have lower bioavailability
1. Animal protein food sources
 Milk
 Egg
 Fish
 Meat
 Chicken
(contain 1-4% of protein)
(± 12%)
(10-20%)
(18-20%)
2. Plant protein food sources
 Grain
products ; rice, wheat (flour)
 Nuts ; (15-25%)
 green bean (± 22,2%)
 soybean (35%)
 peanut (25,3%)
 bean
 kacang bogor
(10%)
 kacang mete
(21,2%)
3. Plant protein food sources :
 Tempe
(10-18%)
 Oncom (13%)
 Tauco (10,4%)
 Tofu (7-8%)
 Emping Melinjo (12%)
 Santan murni (4,2%)
The proteins synthesized in the body
if there were complete and
adequate amount of amino acids.
The quality of protein rely on :
availability of all EAA ; adequate
amount (quantum) that meet the
body need.
Protein quality assessment
 Assessment
of protein quality base
on EAA composition.
 Protein
with complete EAA in
adequate amount is called Protein
Reference or Provisional Amino Acid
Pattern (PAAP)
Amino acids pattern (FAO/WHO, 1973)
EAA
 Isoleusin
 Leusin
 Lisin
 Fenilalanin
 Tyrosin
 AA contain S
 Metionin
 Threonin
 Triptofan
 Valin
mg.AA/gr.nitrogen
250
440
340
200
180
220
220
250
60
310
Source : Wohl & Godhart, 2nd Edition
 EAA in
the food which have lower
concentration (the lowest concentration)
than PAAP ---> Limiting Amino Acid
(LAA)
 Percentage
(%) of LAA ---> Chemical
Score.
Protein Chemical Score ---> EAA value
in the food compared to EAA in PAAP
EAA composition and Chemical
Score
EAA
Prot.Ref. Rice
Isoleusin
250
290
Leusin
440
654
Lysin
340
234
Fenilalanin
200
353
Tyrosin
180
171
Methionin
220
113
Threonin
240
268
Tryptophan
60
66
Valin
310
399
First LAA
Second LAA
Fish
Corn
Soybean
317
228
333
474
535
484
549
268 66% 395
231
351
309
159 88% 217
201
178
117 81%
86 60%
283
268
247
62
219 42%
86
327
324
328
tryptophan
tyrosin
tryptophan methionin
lysin
tryptphan
How to increase protein quality?
- Increase protein quality in the food
- Increase the LAA concentration
---> SUPPLEMENTATION
Two fashions on
supplementation
1. LAA Supplements
- Add crystallized of pure AA
- Expensive , ineffective
E.g. : premix rice
2. Supplementation by one or more
food which contain various LAA
E.g. :
Rice have first LAA, lysin, mix with
peanuts which have first LAA, methionin
Protein metabolism
 Protein
digested by proteolytic enzymes
starting in the stomach ---> in duodenum,
ileum and jejunum ---> form amino acids
 AA absorbed through the intestine by active
transport mechanism and assisted by
carrier protein
 AA ---> portal vein ---> liver
 AA from the liver ---> blood ---> distributed
to the cell organs
 Protein
excretion ---> faeces --->
Undigested Dietary Protein and
endogen protein
 Healthy individual ---> protein does
not excreted through urine, but the
metabolite does
Protein Metabolic Waste Product --->
Urinary Nitrogen : urea and non
protein nitrogen (creatinin and uric
acid)
Amino Acid Pool
 There
are some amino acids in the body
that ready to use by any chance they
needed as energy reserve ; e.g. :
albumin and skeletal muscle cell.
 Amino
acids reserve mentioned above
is called AMINO ACID POOL
 Tissue
amino acids and Amino Acids
Pool are in an equilibrium and
dynamic state.
 Protein
excretion higher than protein intake
will perform negative nitrogen balance -->
reduce body protein --> hypoalbuminemia
or hypoproteinemia
 Protein
intake higher than protein excretion
--> positive nitrogen balance.
Excess protein intake will increase
production of urea, creatinin and uric acid
in the body
Protein RDA on various condition :
 Children
: 1,2-2,2 gr/kg BW/day
 Adult
: 0,8-1,0 gr/kg BW/day
 Pregnancy
: adult + 12 gr/day
 Lactating first
6 month
: adult + 16 gr/day
 Lactating second
6 month
: adult + 12 gr/day
 Lactating
> a year
: adult + 11 gr/day
Diseases related to protein
metabolism disorder
1. PEM (Protein-Energy Malnutrition)
Protein deficiency always happen
simultaneously along with energy
deficiency.
Protein deficiency could occur in
adequate energy intake -->
KWASHIORKOR
2. HOMOCYSTEINURIA
Inborn error of metabolism disease.
Occur in cystathionin synthetase
enzyme deficiency. Methionin
metabolite accumulated and huge
amount of homocystein.
Children usually died at adolescent.
3. PHENYLKETONURIA
Inherited, due to phenylalanin
synthetase enzyme deficiency.
CARBOHYDRATE
Alanine
Cystine
Cysteine
Methionine
Glycine
Serine
Threonine
Aspartic acid
Pyruvic acid
Acetyl CoA
Oxaloacetic
Citric acid
KREB’S CYCLE
Valine
Succinic acid -Keto glutaric acid
Arginine
Histidine
Hydroxyproline
Proline
Glutamic acid
FAT
Acetoacetate
Isoleucin
Leucin
Lysine
Phenylalanine
Tyrosine