-
How many naturally occuring AAs are there?
How many are found in proteins?
How many are essential?
-
What is the common structure of an AA (except proline)?
-
How are AAs chemically classified?
- Based on R group
- Polarity
- Charge
- Hydro -phobic vs -philic
- Branched vs straight
-
How are AAs nutritionally classified?
- Based on dietary requirement
- Indispensible vs dispensible
- Conditionally indispensible
- Semi-indispensible
-
What does semi-indispensible mean?
Can be sythesized from indispensible precursors
- Methionine => Cysteine
- Phenylalanine => Tyrosine
-
What are 3 examples of indispensible AAs?
- Arginine
- Methionine
- Phenylalanine
-
What are 3 examples of dispensible AAs?
-
What are some examples of conditionally essential AAs?
Arginine - poultry, max growth for some species (dogs, cats, pigs)
Proline - hens
Glycine - chicks
Glutamine - intestinal mucosa during illness
-
What is Taurine derived from?
Cysteine
Except in cats, they cannot derive Taruine due to shorter digestive tract
-
What is special about Taurine?
- Not in protein
- Occurs as free AA in cats
-
What configuration do AAs naturally occur in?
L configuration
-
Only L enantiomer absorbed for most AAs except...
D methianine - the body can absorb and convert to L methianine
-
What are the levels of organization in proteins?
Primary structure - AA chain order
Secondary structure - alpha helix or beta sheet domains
Tertiary structure - relationships of domains within a chain, protein folding
Quaternary structure - 2+ polypeptide chains, oligomeric proteins
-
Proteins are classified on the basis of...
-
What are the properties of globular proteins?
- Soluble in water
- Dilute acids and bases
- Alcohols
- Hydrophobic core
- Hyphilic surface
-
What are the functions of globular proteins?
- Enzymes
- Messengers
- Transporters
-
What are the properties of fibrous proteins?
- Insoluble in water
- Resistant to digestive enzymes
-
What are the functions of fibrous proteins?
Structural - collagen, elastin, keratins
-
What are conjugated proteins?
Contain non-protein compounds
- Lipoproteins
- Glycoproteins
- Mucus
-
The body cannot absorb intact proteins. What is the one exception to this?
Collostrum from breast milk for a short period after birth
-
What are the different forms of protein digestion and absorption?
- Cooking
- Stomach acid
- Small intestine pH, pancreatic proteases, zymogens, cleaving enzymes, active enzymes
- Proteases
-
What are zymogens?
Inactive precursors of active enzymes so that intestinal wall is not digested.
-
What are the different cleaving enzyme classifications?
- Enterokinase
- Endopeptidases
- Exopeptidase
- Active Enzymes
-
What does enterokinase do?
Cleaves trypsinogen to trypsin
-
What are some examples of endopeptidases?
- Pepsin
- Trypsin
- Chymotrypsin
- Elastase
-
What is an example of an exopeptidase?
Carboxypeptidase
-
What are some examples of active enzymes that cleave specific peptide bonds?
- Chymotrypsin
- Elastase
- Carboxypeptidase
-
INSERT SLIDES FROM PAGE 6/7 HERE
-
What are some signs of protein deficiency?
- Reduced growth
- Decreased feed efficiency
- Kwashiorkor - Edema
Pregnant - Reduced birth weight, milk production
-
How do AAs regulate protein synthesis?
Protein synthesis can only occur until the first "limiting" AA is used up, the other AAs are broken down (oxidized)
-
What are 3 AA interactions?
Antagonism - reduction in performance that can be overcome by supplementation of a structurally similar AA, ex. lysine and arginine
Toxicity - adverse reactions of an AA can not be overcome by suplementation of other AA
Imbalance - dietary proportions of indispensible AA do not meet needs of animal, can be overcome by supplementation
|
|
