Protein Flashcards
Composed of C, H, O, N, and sometimes S
Protein
Only nutrient that can make new cells and rebuild tissue.
Protein
Basic material of every body cell.
Protein
Composed of amino acids linked by peptide bonds.
Protein
Greek word that means “holding first place” and term coined by Mulder (Dutch Scientist) in 1840.
Protein
Molecule w/ a central carbon to which an amino group, a carboxyl group and a functional group are attached.
Amino acid
How many amino acid are needed by the human body?
20
How many from the 20 AA are considered essential, which must be supplied by the diet?
10
General structure of AA
central carbon, amino group, a carboxyl group and a functional group
AA classification
Functional groups, Pathway of catabolism, essentiality
Functional groups
Basic, acidic, neutral
Basic Functional group AA
lysine, arginine, histidine
acidic Functional group AA
aspartic acid, glutamic acid
neutral Functional group AA
glycine, serine, threonine, etc
2 pathway of catabolism
glucogenic, ketogenic
AA that can be catabolized to produce glucose (gluconeogenesis)
glucogenic
AA that can be catabolized to produce acetyl-CoA (-> ketone bodies) and ipids
ketogenic
3 classifications of Essentiality of AA
essential, nonessential, conditionally essential
Indespensable AA
Essential
Dispensable
Nonessential
Indispensable at certain life stages
Conditionally essential
Essential AA
(PVTTIMHALL) Phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, arginine, leucine, lysine
Conditionally essential
Proline, serine, tyrosine, cysteine, taurine, glycine
Nonessential
Glutamate, alanine, aspartate, glutamine
Protein classification
structure, shape, composition
4 levels of protein structure
primary structure, secondary structure, tertiary structure, quaternary structure
Classification of protein by shapes
fibrous, globular, membrane
Proteins which are long coiled or folded chains of AA bound in parallel line and insoluble in water and dilute salt solutions; serve in structural roles
Fibrous
Protein which are coiled, tightly wound structure & roughly spherical; relatively water soluble; constitute most of the soluble proteins in the cell
Globular
Proteins associated with various membrane systems; insoluble in aqueous solutions; more hydrophobic AA
Membrane
Example of Fibrous protein
keratin
Example of globular protein
hemoglobin
Example of membrane protein
phospholipid membrane
Protein classification by composition
simple, conjugated, derived
Protein which are primary components are AA
simple
Proteins which are composed of AA and other components
conjugated
Proteins which are products of partial hydrolysis
derived
Examples of simple proteins
albumin (egg white), globulins (egg yolk), glutenins or glutelins (wheat, rice), prolamines (wheat, corn) scleroproteins (bones, connective tissues)
protein source with amino acid score: 100%
animal origin
Biological functions of protein
Enzymes - to accelerate rates of biological reactions
Regulation of body processes - to assist in the ability of other proteins to carry out their functions (hormones)
Storage - to provide reservoir like hemoglobin
contraction and motility - for muscles
structure - to provide strength like collagen and keratin
protection - to enhance immunity like immunoglobulins
amino acid score of animal origin
100%
Examples of conjugated proteins
glycoproteins, lipoproteins, nucleoproteins, phosphoproteins, metalloproteins, hemoproteins, flavoproteins, mucoproteins
General functions of protein
- body building or structural
- essential for growth
- source of energy (secondary)
- regulator of body processes
- transport of certain substances
Examples of derived proteins
Primary - edestan, myosan, metaproteins, coagulated proteins
Secondary - proteoses, peptones, and peptides
protein source with true digestibility: 95-98%
animal origin
true digestibility of animal origin
95-98%
protein source which concentrations increase after cooking
animal origin
protein source which includes pulses, cereal & cereal products
plant origin
protein source with amino acid present, could be 1 or more limiting amino acids
plant origin
plant origin examples
pulses, cereal & cereal products
how many limiting amino acid present in a plant origin?
one or more limiting amino acids
protein source with true digestibility in natural foods: 70-85%
plant origin
true digestibility of plant origin
70-85%
bioavailability of protein in pulses
20-25%
bioavailability of protein in flour
7-12%
meat alternative made from soy protein and other ingredients to simulate various kinds of meat
meat analogues
textured vegetable protein (TVP) and tofu
meat analogues examples
Capacity of food proteins to provide nitrogen and essential AA for human growth and functions
Protein quality
- checks AA content & efficiency of digestion
- lower protein quality means more intake of protein
What highlights nitrogen balance
Protein quality
reflects the equilibrium between protein intake and losses
nitrogen balance
Nitrogen balance
equilibrium: intake = output
positive nitrogen balance: intake > output (children, pregnant, convalescing person/recovering)
negative nitrogen balance - intake < output (underwent surgery, fever, immobility, shock, burns)
Factors affecting protein utilization
- AA balance
- emotional stress
- caloric intake
- inborn errors of metabolism
- food processing
How to determine protein quality
- biological value
- amino scoring
- protein digestibility
- protein conc.
- protein/energy ratio
refers to percentage of nitrogen absorbed from the dietary protein actually used by the body
biological value
-higher BV -> higher N retained; means the food is supplying essential AA
Formula of biological value
BV = (N retained) / (N absorbed) = ((Dietary N - (Urinary N - Fecal N)) / Dietary N - Fecal N) x 100
BV of some foods
Egg: 100
Milk: 93
Rice: 86
Fish, beef: 75
Corn: 72
Peanut flour: 56
Wheat gluten: 44
Calculation of the proportion of each EAA in protein or diet relative to reference protein
AA Scoring
Value of the limiting AA with the lowest score in a protein
AA score (chemical score)
Formula of AA score
AA score = (mg of EAA in 1g of food protein) / (mg of EAA in 1g of reference protein)
Measure of the amount of protein available for absorption after digestion that is dependent on the shape (fibrous or globular), presence of dietary factors, and heat treatment
Protein digestibility
A variation of protein digestibility that has been developed
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
provides adequate amounts of essential amino acids to adequately support human protein synthesis
plant combination
official assay for evaluating protein quality in human nutrition
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
complementary proteins of Kanin + Munggo Guisado
High Met (rice) + Low Met (beans)
Chemical score of limiting AA multiplied by its true digestibility
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
Complementary proteins of mais con yelo
High Lys (milk) + Low Lys (corn)
PDCAAS Formula
PDCAAS = ((mg of 1st limiting AA in 1g test protein) / (mg of the same AA in 1g reference protein)) x TD (%) x 100
TD is true fecal digestibility of the test protein
excellent protein combinations of grains and legumes
-rice + beans
-pea soup + toast
-lentil curry +rice
to rate the overall quality of protein based on the amount of essential AA contained
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
excellent protein combinations of grains and dairy
-pasta + cheese
-rice pudding
-cheese sandwich
Based on the AA that is in the shortest supply when compared to the reference (scoring) protein
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
This scoring pattern is based on the IAA requirements of preschool-age children
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
excellent protein combinations of legumes and seeds
-garbanzo beans + sesame seeds
-hummus (dip or soup)
Digestibility of protein is factored into the score by way of fecal digestibility
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
addition of protein rich food to a regular diet to increase protein content and quality
protein supplementation
PDCAAS Example
common digestibility percentages include 98% for egg protein; 95% for casein, soy and collagen; 91% for wheat protein
increase protein content and quality
addition of protein rich food to a regular diet
How to interpret PDCAAS
If a protein is completely missing just one essential AA, the PDCAAS is 0.
If a protein with a low amount of one essential AA ha a PDCAAS of 20, then the protein provides only 20% of that particular AA when compared to the scoring pattern.
Thus, only 20% of this protein is possible available for protein synthesis in the human body.
example of protein supplementation
-Tuna spread + cheese = Tuna Melt Sandwich
-Pasta + Ground Beef + Cheese/Cream = Lasagna
Protein concentration (density)
—-table—-
-Tuna spread + cheese = Tuna Melt Sandwich
-Pasta + Ground Beef + Cheese/Cream = Lasagna
example of protein supplementation
To describe whether a diet provides adequate amounts of protein
- indicates the amount of protein that the diet provides relative to energy
Protein/Energy Ratio (net dietary protein calories present)
protein turnover is composed of
SYNTHESIS where amino acids are joined to form peptides and protein AND DEGRADATION which results in amino acids that are recycled
Formula of protein/energy ratio
((metabolizable energy from dietary protein) / (metabolizable energy in diet)) x 100
Formula on %protein calories
(protein calories/total kcal intake) x 100
amino acids are joined together to form peptides and protein
Synthesis in protein turnover
meat analogues examples
textured vegetable protein (TVP) and tofu
amino acids are recycled
Degradation in protein turnover
Fusarium graminearum
a mycoprotein example of meat analogue
dependent on the simultaneous presence of all the amino acids for the specific protein & energy
Protein synthesis
substances/structures that require protein synthesis
cells, glands, muscles, organs, fluid and secretions
a mycoprotein example of meat analogue
Fusarium graminearum
metabolic events in Cell Nucleus
Site of synthesis for these metabolic events:
-DNA serves as templet for mRNA
-mRNA copies DNA code
-mRNA leaves the nucleus
Cell nucleus
meat analogue has _____ digestibility
higher
metabolic events in Ribosomes in the Cytoplasm
-mRNA attach to ribosome to specify sequence of amino acid
-tRNA collect amino acids from cell fluid and brings these to mRNA which specifies amino acid sequence
-ribosome moves along mRNA as each amino acid is brought by tRNA
-completed protein is released from ribosome and mRNA is degraded
proteins which contain all essential amino acids in amounts sufficient for growth & maintenance
complete or high biological (HBV) proteins
Site of synthesis for these metabolic events:
-mRNA attach to ribosome to specify sequence of amino acid
-tRNA collect amino acids from cell fluid and brings these to mRNA which specifies amino acid sequence
-ribosome moves along mRNA as each amino acid is brought by tRNA
-completed protein is released from ribosome and mRNA is degraded
Ribosomes in cytoplasm
site of protein synthesis which consists of RNA and protein
Ribosomes
all animal origin foods except gelatin
complete or high biological (HBV) proteins
proteins which maintain life but do not support growth
partially complete proteins
What are the genera principles of protein metabolism?
-amino acid are in dynamic state
-proteins must be supplied to the body on a daily basis
-synthesis of proteins is controlled by DNA
-synthesis of proteins follow the all or none law
-protein utilization is closely interrelated w/ fat & carbohydrate metabolism
-amino acids can be recycled
gliadin (wheat) and legumin (legumes)
partially complete proteins
amino acids are in a _______ state
dynamic
proteins which cannot support life or growth
incomplete proteins
zein (corn), gealtin, and most plant proteins
incomplete proteins
synthesis of proteins follow the ______ or _______ law
all, none
plant combination which provides adequate amounts of essential amino acids to adequately support human protein synthesis
protein complementary
synthesis of protein is controlled by
DNA
Proteins must be supplied to the body on a ______ basis
daily
protein utilization is closely interrelated with _______ & _______ metabolism
fat, carbohydrate
__________ can be recycled
amino acids
results in amino acids that join the amino acid pool
Protein degradation
process of protein degradation
protein -> peptide -> amino acids;
nitrogen - incorporated in niacin & creatinine
proteins (ex. proline, glitamate, serine, and threonine) degrade at different rates based on
physiological status and amino acid composition
fates of amino acids not used for synthesis
-DEAMINATION (transamination, oxidative deamination, deamination by amino acid oxidase)
-CARBON SKELETONS (oxidized, synthesis of glucose or fatty acids)
transamination, oxidative deamination, deamination by amino acid oxidase
DEAMINATION
oxidized, synthesis of glucose or fatty acids
CARBON SKELETONS
What are the protein (CHON) requirements (g/kg DBW) for each age group?
Infants - 2.75 to 3.00
Children - 1.50 to 2.00
Early Adolescents - 1.50
Older Adolescents - 1.25
Adults - 1.12
Protein which is 10-15% of TEA is affected by what factors?
- Body size
- Growth
- Pregnancy and Lactation
- Aging
state of deficit in body protein or in or more of the essential amino acids
protein deficiency
signs of protein deficiency
wasting of tissue, weight loss, general weakness and malaise, reduced resistance to infection, dry and scaly skin, delayed wound healing, nutritional edema, hypoproteinemia, and pallor (anemia)
results from inadequate dietary protein, energy or both
protein energy malnutrition
protein energy malnutrition common in 1-3 years of age can cause
mortality, morbidity, and impairment of physical and mental growth
types of prolonged protein energy malnutrition
- Kwashiorkor
- Marasmus
disease occurs when the next baby is born, inadequate protein intake with fair or normal intake of energy , occurs during weaning stage where foods which lacks amino acids are given to child
Kwashiorkor
results from deficiency of both protein and energy (predominantly energy deficiency)
Marasmus
characteristics of marasmus
wasting, emaciation, no edema, quiet, apathetic
not toxic but taxing to liver, kidneys, and circulatory system
excess protein
infants -> increase in ____ and _____ (not to exceed: ___ g/kg/day)
BUN, creatinine, 3
excess protein with adequate CHO and fat lead to
adiposity or obesity