Proteins Flashcards
The word protein was derived from the Greek word ——- which means the —— (——– —— ———)
proteios; first (the most important).
Proteins are organic nutrients; highest concentration in —— —— of animals.
muscle tissues
Proteins are Expressed in terms of —— ——
crude protein (CP).
CP = ———- + — ——- ——
CP = true protein + non-protein nitrogen (NPN
Formula for Crude Protein
CP = %N × 6.25%
are proteins which are composed of amino acids only.
True proteins
—— ——- —–are compounds which are not true protein in nature but contain nitrogen (N) that can be converted to protein by ——– ——.
Non-Protein-Nitrogen; bacterial action.
Normally, —— animals receive a diet higher in protein content than
——- and ——— animals.
young; growing and mature
Young animals require high amount of amino acids to
support growth of tissues.
Mature animals need amino acids largely for
maintenance of protein tissues.
Proteins are large molecules with molecular weights ranging from —– to —- ——–.
5000 to many millions.
Proteins are chemically made up of
C (50-55%), H (5-8%), O (20-25%), N
(15-17%), S (1-3%) and P (0.20-1.5%).
Proteins are made up of molecules of —— —— which are linked
together by —— ——-
amino acids; peptide bonds
The amino acids are organic compounds that contain
one or more amino group (NH2).
Proteins contain —- —- – amino acids; polypeptides contain —- —- – amino acids.
more than 70; less than
70
ontains only amino group and lacks the carboxylic acid group
as compared to amino acid structure
Non-Protein-Nitrogen Source
NPN with 1 N -
NPN with 2 N -
NPN with 3 N -
Ammonia
Urea
Biurey
have a fiber structure and are insoluble in water; serve predominantly as supporting and ground substances. Ex. —— in hair; —— and —– in connective tissue.
Scleroprotein
Keratin; collagens and elastins
are more or less strongly coiled and are soluble in water and salt solutions. Ex. —— in the nucleus, albumins and
globulins
Spheroproteins
Histones
contain amino acids which can be
split-off relatively easy
Conjugated Proteins or Proteids
in hemoglobin;
in casein;
in serum liprotein,
in nucleic acid;
in seromucoid and
in myoglobulin).
Metalloprotein
phosphoproteins
lipoprotein
nucleoprotein
glycoprotein
chromoprotein
proteins that yield only amino acids or their derivatives upon hydrolysis.
Simple Proteins
these are proteins conjugated with a non-protein radical (prosthetic group).
Conjugated Proteins
• – conjugated to nucleic acid (DNA and RNA)
• – with phosphate (casein of milk)
• – contains a metal ion cofactor (cytochrome oxidase)
Nucleoproteins
Phosphoproteins
Metalloprotein
• – conjugated to lipid (very low density lipoprotein)
• – contain a nucleic acid derivative of riboflavin (flavin-adenine
dinucleotide or FAD)
• – contain oligosaccharide chains (immunoglobulins)
Lipoprotein
Flavoprotein
Glycoprotein
contain one amino acid and one carboxyl group
Neutral amino acids
3 types of Neutral Amino Acid
Aliphatic Amino Acids
Aromatic Containing Compounds
Sulfur Containing Compounds
Aliphatic amino acids (7)
glycine, alanine, valine, leucine, isoleucine, serine and threonine
Aromatic amino acids (3)
phenylalanine, tyrosine, tryptophan
Sulfur containing amino acids (3)
cystine, cysteine, methionine
have an excess of carboxyl over amino groups
Acidic amino acids
Acidic Amino Acid (2)
Aspartic Acid and Glutamic Acid
– possess an excess of basic groups
Basic Amino Acids
3 Basic Amino Acids
Histidine Arginine and Lysine
have imine functional group
Imino acids
2 Imino Acids
Proline and Hydroxyproline
• amino acids which are essential to the animal
• must be supplied to the diet because the animal’s body cannot synthesize
them fast enough to meet needs for these amino acids.
Essential Amino Acids (EAA)/Indispensable Amino Acids (IAA)
makes up 40% of tissue protein
• amino acids which are needed by animals but can be synthesized by them in amounts sufficient for their needs.
Non Essential Amino Acids/Dispensable Amino Acid
with — —– – ——, tissue synthesis of —– occur provided that there is adequate supply of amino nitrogen and source of carbon and energy.
With Low intake of Non Essential Amino Acids
Amino acid which is present in a protein in the least amount in
relation to the animal’s need for that particular amino acid
Limiting Amino Acid
first limiting amino acid of corn-soy diets in growing pigs
Lysine
common limiting amino acids in
poultry diets especially in corn-soy diets
Methionine and cystine
A protein of high quality contains the —– in amount and relationship
corresponding to the requirement of the animal.
Essential Amino Acids
——– protein sources (e.g. fish meal and skimmilk) are generally
superior in protein quality than —– protein sources (e.g. soybean
meal; ipil-ipil leaf meal).
Animal; plant
Denaturation of proteins by the ——— —— secreted by the stomach (proventriculus in poultry) leading to the change in the native
structure of protein
hydrochloric acid (HCl)
Digestion of denatured protein digestion at — – (–) through the
action of enzyme —– that results to the formation of large peptides
and amino acids
Low ph 2.1; pepsin
Translocation of peptides and amino acids to the —– —— and
which they are acted upon further by specific enzymes: ——-, ——–, ——-, ———-, ——-, ——–
Small intestine; chymotrypsin, carboxypeptidase, aminopeptidase, nucleotidase and
nucleosidase
are absorbed and transported to the liver via portal circulation where they are metabolized.
freed amino acids
Factors Affecting Protein Digestion by Non-Ruminants
- Age of Animal
- Presence of Protease Inhibitors
- Excessive heat processing of feeds
low protein digestibility during the first —— —— due to
limited amount of digestive enzymes; digestibility increases within this
period (- to - —–) then not much change after.
Age of Animal; Four weeks (1 to 4 weeks)
——- ——- in raw soybeans,
—– —– in rice bran,
—— in peas,
in by-product feeds and
in cereals (e.g. barley and wheat) and ——– (soybean);
these inhibitors limit the activity of enzymes for protein digestion.
Trypsin Inhibitor
Phytic acid
lectins
fiber
non-starch polysaccharides (NSP)
legumes
Presence of Protease Inhibitors
Excessive heat processing of feeds – cause ——-/——- reaction that
leads to the binding of amino acids such as lysine with glucose or lactose
rendering them biologically unavailable.
Maillard/Browning
The rumen organisms are capable of utilizing almost any nitrogen
source to create ———- (serves to provide protein needs of
the ruminant animal) and thus enable the ruminant animal to use
——- which are unsuitable for use by non-ruminant animal
bacterial protein; feedstuffs
About what percent of the true protein escapes microbial action in the rumen??
What do you call about the protein that escapes microbial action in the rumen that passes into the abomasum and small intestine where it is absorbed and digested in the same
manner as in the non-ruminant?
40% ; escape protein or by-pass protein
The dietary NPN and the remaining portion of the true protein (about
—%) are acted upon by the —– ——- forming ammonia (NH3).
60%, rumen microflora
With adequate amounts of fermentable carbohydrates, the —-
is used by the rumen bacterial to form bacterial protein.
NH3 (Ammonia)
The bacterial protein then passed into the ———– and digested as
previously presented for non-ruminants
abomasum
The ——- —— which is formed may be of better or poorer quality
than that of the ingested feed
microbial protein
Usually, the quality of protein from moderate to poor diets may be
improved by —– ——- while the quality of protein of good to high
quality protein may actually be ——.
Rumen metabolism; reduced
—% of the bacterial species in the rumen utilize nitrogen solely for growth, —-% have absolute requirement for nitrogen, —- use either ammonia
(NH3) or amino acids.
80%, 26%, 55%
cannot utilize NH3; they consume bacteria as a source of nitrogen and also from particulate matter.
Protozoa
Unused quantity (by rumen microbes) of NH3 are transported to the
—- and converted into —-.
Liver; Urea
Urea is either excreted by the —— through the urine or recycled
into the rumen by way of the —–.
Kidney; saliva
If the amount of NH3 which enters the bloodstream is excessive and
exceeds the ability of the animal to excrete it, it can lead to ——- and —–.
toxicity and death.
Factors Affecting Protein Digestion by Ruminants
Availability of ——– ——-
Quantity of —- ——- and —- (specific need of the rumen microflora)
• —– —— (related to quantity of fermentable carbohydrates)
• Degradability of the —–
• —— population
fermentable carbohydrates
true protein and NPN
Dietary energy
protein
Microbial
Fates of Absorbed Amino Acids
- new and replacement of worn out
tissues.
• Collagen
• Elastin
• Contractile proteins
• Ketratin
• Blood protein
- new and replacement of worn out
- Used in —- ——-
• Enzymes – digestion, anabolism and
catabolism
• Hormones
• Immune bodies - – release of
amino group from the carbon
skeleton and entry of the
carbon skeleton to the Kreb’s
Cycle.
- Use as a basic structural unit of the Animal
- Used in body metabolism
- Source of energy after
deamination
the key organ in nitrogen metabolism
Liver
Functions of Liver
• —– ——
• Supply of —– —– to the ——– when needed
• Processes ——– for ——– when in excess
Protein synthesis
Supply of amino acids to the circulation when needed
Processes nitrogen for excretion wgen in excess
occurs in the mitochondria;
Transamination
permits exchange of ammonia from an amino acid to the keto moiety of an alpha-keto acid.
Transamination
Transamination promotes the following events:
a. Excess amino acid can be relieved of their NH3 and the keto acid
metabolized in the TCA cycle for ——-
b. Synthesis of —- from glutamic acid and TCA intermediates.
Energy generation; NEAA
are the most important enzymes for transamination.
Glutamic acid transaminase and alpha ketoglutaric acid transaminase
• Of the EAA, only —– and ——– do not participate in transamination.
lysine and threonine
Transamination is a ——- process and requires —— as a cofactor
Reversible; vitamin B6
is the removal of amino group from amino acids.
Deamination
Two types of Deamination
Oxidative and Non-Oxidative
it occurs in the cytosol and mitochondria of most cells.
Oxidative
the principal enzyme involved in the process of deamination is - - ——— ———–.
L-glutamate dehydrogenase.
NH4 enters —- Cycle and alpha-ketoglutarate enters — Cycle
Urea cycle and TCA Cycle
catalyze by amino acid dehydratase and requires vitamin B6
Non-Oxidative
is the principal activity of the cell.
Synthesis of protein
is the template of protein synthesis thru transcription followed by Translation.
DNA
(copying a segment of DNA to mRNA)
Transcription
(translating the sequence of mRNA to a sequence of amino acids)
Translation
Three RNAs are involved in the process, namely
mRNA
rRNA
tRNA
determines sequence of amino acids in the protein being formed;
Messenger RNA (mRNA)
constitutes 2/3 of the mass of ribosome, part of the structure of ribosome which is the site of protein synthesis.
Ribosomal RNA (rRNA)
smallest of the RNAs; carries specific amino acid to be
incorporated in the polypeptide chain;
Transfer RNA (tRNA)
there are – separate tRNA – –
attuned to specific amino acid; - signals peptide chain termination.
64; 61; 3
requirement can be met only by providing adequate
levels of methionine in the diet.
Methionine
requirement can be met by methionine + serine
Cystine
requirement can be met only by phenylalanine
Phenylalanine
requirement can be met by phenylalanine
Tyrosine
– can be used interchangeably
Glycine and Serine
Advantages of Expressing Amino Acid Needs Based on Digestible Amino Acids
- Improves —— and —— of feed manufacturing.
- Real — —- —- ——- can be obtained.
- —— —— —– is more indicative of the relative nutritional
value of feedstuffs. Allows use of protein feeds of poor quality at
high levels. - ——– ——- of protein/amino acids.
accuracy and precision
low-cost feed formula
Digestible amino acid
Minimize wastage
high dietary level may compensate for a deficiency of choline or vitamin B12 by providing methyl group.
Methionine
alleviates niacin deficiency through metabolic conversion to niacin.
Tryptophan
most metabolic activities are depressed with —– ——–;
there are no specific set of deficiency signs for protein.
Protein deficiency
With low protein intake the following can be observed:
b. Growth is ——– (as in the case of ——– which is
protein malnutrition in young humans)
c.
d.
rumen fermentation
impaired; Kwashiorkor
Sub-optimal reproduction
d. Sub-optimal lactation and reproductiob
a deficiency of any of the essential amino acids is in effect a protein
deficiency.
• an amino acid deficient diet causes prompt ——- in —– ——
of an animal.
Amino acid Deficiency;
reduction in feed intake
this results from the addition to a low protein diet of one or more
amino acids, other than the growth limiting one, in amounts that are
not individually toxic and yet causes depression in food intake and
growth that are readily prevented by a supplement of the —— ——– —– —-
Amino acid imbalance
growth-
limiting amino acid.
it is a condition wherein one amino acid affects the requirement of
another by interfering with its metabolism.
Amino acid Antagonism
Example of Amino Acid antagonism
Lysine-arginine antagonism
——- (given at high level) increases the requirement for arginine
by competing with arginine for reabsorption in the —– ——
increasing arginine excretion and by increasing renal arginase
activity and thus splitting arginine into —– and ——–.
Lysine
renal tubules
urea and ornithine
