Proteins Flashcards
*Explain what a complete protein is
Contains all 9 esseential amino acids
*THREE examples of complete proteins.
Quinoa, chia, hemp, pumpkin seeds, buckwheat, animal protein
*TWO hormones tyrosine rquired for.
Dopamine, adrenaline and noradrenaline
Thyroid
*Why can oedema occur when protein levels fall too low?
Albumin draws water in therefore will seep into interstitial fluid if insufficient. And maintains oncotic pressure.
*What is importance of ‘transamination’?
To create nother non-essential amino acid from another amino acid. Breaks down amino acids.
*Explain what happens in urea cycle.
Can’t utilise protein for fuel / convert protein to storage if amine group is still attached.
When nitrogen group is removed from amino acid, toxic ammonia is formed.
Ammonia has to be converted to water-soluble compound, via series of transformation reactions in liver (known as urea cycle) to ensure that it can be excreted by kidneys as urea as part of urine.
*Outline TWO ways to optimise digestion of protein.
1.Sit and be calm. Parasympathetic.
2. Chew thoroughly and avoid drinking with meals.
3. Support stomach acid levels:
– Zinc and B6-rich foods (HCl).
– ACV in a little water before meals (10 mins)
– Bitter herbs and foods before meals (eg dandelion, rocket,
watercress, artichoke, gentian, barberry bark, goldenseal). Stimulate release of HC and pancreatic juice.~
3. Betaine hydrochloride supplements (min 600mg / capsule).
Start with one when starting to eat, before increasing one capsule per meal up to a total of 5 max or feeling of warmth. If warm, cut one pill back.
*Protein in plant foods is often referred to as incomplete. Why is this and how can different foods be combined to overcome it?
Does not contain all 9 essential amino acids or insufficient amounts.
Combine different plant proteins throughout day eg legumes and wholegrains, veg with legumes.
*What are THREE adverse effects associated with long-term high intake of animal protein?
Increases cancer, diabetes risks.
Increases acidy in the body. Will buffer by releasing Ca from bones.
Shortened life span.
1. Highly acidic-forming causing cancer, RI, arthritis and diabetes.
2. Strain on digestive system - may cause food to putrify reducing absorption.
What % of body weight does protein account for?
17%
How many proteins will an average cell produce in its lifetime?
10,000 different proteins
How many amino acids are there in nature?
1000 (and 1,000 therapeutic mushrooms!)
What x3 does each amino acid contain?
- Amino group – NH2
- Carboxylic acid group – COOH
- Unique side group (R-group) which differentiates amino acids
How many amino acids do humans use?
20
Polypeptide meaning?
Amino acids in a chain. Another word for protein.
What is structure of an amino acid linked to?
Its function.
Amino acid chain (‘primary structure’) folds in a certain pattern to create its 3D structure. This structure is closely linked to function of protein (i.e. lock and key).
How many non-essential amino acids are there in body?
11
Conditionally essential amino acids?
Eg in pregnancy, recovering from illness. Insuffiicent quantities available as demand is greater.
Name 9 essential amino acids
Isoleucine
Phenylalanine
Leucine
Lysine (limiting AA)
Valine
Threonine (limiting AA)
Tryptophan (limiting AA)
Histidine
Methionine (limiting AA)
PVT TIM HiLL (Private Tim Hill)
Name conditionally essential AAs (amino acids)
Conditionally Essential = CAT GGP
Cysteine
Arginine
Tyrosine
Glutamine
Glycine
Proline
How do proteins become denatured?
- Exposed to heat
- Variations in pH
- Alcohol
- Heavy metals eg aluminium, mercury.
What happens when proteins are denatured?
Lose their 3D structure and hence their function.
structure effectively unravels.
FIVE functions of protein in growth and development
- Building blocks of muscles, blood, dermis, and most body structures.
- Actin and myosin filaments involved in muscle contraction
- Bones are formed of a collagen matrix; provides framework for minerals deposition (lysine part of collagen)
- Collagen provides building material for ligaments, tendons, blood vessel walls, skin.
- Replacement of cells eg skin, GIT cells.
Name four amino acids that make hormones
-
Tyrosine (fish) and Iodine (seaweed/kelp) used to produce:
- thyroid hormones
- dopamine
- norepinephrine
- epinephrine. -
Tryptophan (turkey, bananas) produces:
- serotonin
- melatonin. - Two polypeptide chains eg insulin
- Glucagon, PTH, calcitonin: produced from one polypeptide chains.
NB Cell membrane proteins are receptors for hormones.
Proteins have key transport (taxi!) role. Name 3.
- Albumin can bind to calcium, zinc and B6, as well as steroids and fatty acids.
- Transferrins bind to iron.
- Ceruloplasmin binds to copper.
- Haemoglobin transports oxygen in blood.
Low stomach acid name?
Hypochlorhydria
Function of amino acid R groups?
- Determines AA function
- Buffers: Easily pick up/let go of hydrogen ions which help to regulate acid-base balance.
Two AA buffers
Histidine (primary) and cysteine.
What is oncotic pressure?
Proteins attract water which exerts osmotic pressure which called oncotic pressure. Stops water leaking out of blood vessels and acumulates in interstitital spaces causing oedema.
THREE protein-related causes of oedema
- Excessive protein losses due to kidney disease.
- Inadequate protein synthesis due to liver disease.
- Inadequate dietary intake of protein (malnutrition).
What is a glycoprotein?
Type of protein molecule that have sugar (carbohydrate) chains attached to them
Name three glycoproteins
- Mucins – found in mucus and saliva; provide a protective, lubricating barrier.
- ABO blood (type) antigens.
- Hormones – incl. LH, FSH, TSH
- Major Histocompatibility Complex ~cell surface receptors involved in adaptive immunity eg antigen presentation.
- Proteoglycans
What are proteoglycans?
Subclass of glycoprotein.
Bound to glycosaminoglycans (GAGs) and found in extracellular matrix eg chondroitin sulphate, found in cartilage – shock absorbs (NB protein absorbs water).
Deamination?
Removal of nitrogen-containing amino group (by liver hepatocytes)
Purpose of deamination?
Following deamination remaining AA fragments may be used:
- To produce glucose or ketones.
- These can be used as energy or to become energy storage.
Which two AAs are produced via Urea cycle?
- Arginine
- Citrulline
- Plus ornithine (an important liver support and detox agent)
Urea Cycle is sole endogenous source of amino acids.
Symptoms of hyperammonaemia (too much ammonia)?
- Chronic fatigue
- Headache
- Irritability
- Nausea
- Diarrhoea
- Poor concentration
- Confusion,
- Intolerance of high protein foods.
Transamination?
If a particular non-essential amino acid is not available, body can make it from another.
Amino group, enzyme, ketoacid. B6.
- AA Amino group transferred onto
enzyme. - Transferred to ketoacid, thus forming new amino acid.
- B6 as a coenzyme.
B6 deficiency will impair this process.
B6 use
- Nervous system (neurotransmitters)
- HCL
- Krebs cycle.
Widely available but digetive system maybe compromised if insufficient - Transanimation
- Converting glutamate to GABA
Where is B6 available?
Wholegrains, green vegetables, sunflower seeds, pistachios,
walnuts, bananas, lentils, avocados, meat & fish
BAM
Bananas, avo, near meat
Protein turnover - how long does a protein last?
Amino acids cannot be stored in body - utilised or excreted out. Essential amino acids generally have a longer half-life.
Proteins continually being broken down eg enzymes maybe recycled in a matter of minutes.
Amino acid pool?
When body proteins break down, the free amino acids join general circulation; these amino acids + diet-derived amino acids
What effect does stress have on bodily protein?
Causes protein losses in eg skeletal muscles due to catabolic actions of cortisol.
Chronic stress impacts extracellular matirix ie collagen.
Leads to oesteoporosis.
From which tissues does adult human body reabsorb protein?
Endogenous sources:
- 50g from shed mucosal cells (gut lining)
- 17g from digestive enzymes and glycoproteins
How to counter anti-nutrients eg phytates and lectins?
Soaking, sprouting and fermenting. Also high-steam cooking.
Name of supplement to increase HCL
Betaine hydrochloride. At least 600mg per capsule.
Start with one when starting to eat, before increasing one capsule per meal up to a total of 5 max or until a feeling of warmth. If warm, cut one pill back
Limiting amino acid?
If an essential amino acid is supplied in less than amount needed to support protein synthesis, it is called a limiting amino acid.
To make proteins, a cell must have all required amino acids available simultaneously; if one essential amino acid is missing, a cell will have to cease making protein or must dismantle another protein to obtain it.
Name FOUR limiting amino acids
- Threonine (grains)
- Tryptophan (corn)
- Methionine
- Lysine
Name five vegan sources of nine essential amino acids
- Quinoa
- Buckwheat
- Pumpkin seeds
- Chia seeds
- Hemp seeds
- Tempeh
- Macadamia nuts.
Combine beans with what to get all 9 essential amino acids?
Nuts (methionine missing)
Beans and nuts.
Combine grains with what to get all 9 essential amino acids?
Legumes - Lysine and threonine missing
Combine nuts and seeds with what to get all 9 essential amino acids?
Legumes - Lysine missing
Combine vegetables with what to get all 9 essential amino acids?
Grains, nuts, seeds (methionine missing)
What carcinogens build up during high temp cooking of meat?
- Polycyclic aromatic hydrocarbons (PAHs)
- Heterocyclic amines (HCAs)
eg frying, BBQ, high temp-roasting = carcinogenic.
What is TOR?
Target Of Rapamycin
Enzyme that regulates cell growth.
Three non-protein uses of amino acids?
- Contribute to synthesis of hormones and neurotransmitters.
- Act as neurotransmitters themselves eg glycine.
- Act as methyl donors eg methionine.
- Build bile acids for digestion (glycine and taurine).
- Act as precursors for nitric oxide production eg Arginine.
- Help P2 liver detoxify thousands of chemicals (i.e. phase 2 liver pathways).
- Act as precursors for manufacture of endogenous antioxidants.