~20% of RMR

(10-25%)

 This method of protein quality assessment is required for labeling foods consumed by adult 

3 methylhistidine

 A person with maple syrup urine disease needs to restrict intake of

The number of metabolically essential amino acids

A marked increased ammonium in the urine results when ____

The final produt of protein digestion in the intestinal lumen

Carnitine is synthesized for

lysine and methionine

Dietary proteins are converted to free amino acids primarily in the ___ before the free amino acids enter the blood.

Throixin

When evaluating protein quality which of the measures represents the gain in body weight on a test protein divided by the grams of protein consumed?

Secondary structure

Tiertiary structure

is when at least 2 peptide units bind to each other.

Ex. Insulin, Hemoglobin

Nitrogen

A Carboxyl group

A R group

The most limiting amino acids for infants worldwide include: 

Methionine
Threonine

Lysine

Essential Amino Acids

(indispensable)

 When the diet is lacking the amino acids tyrosine and glutamate.

A function of hydrochloric acid in gastric juice during protein digestion is

 To denature the quaternary, tertiary and secondary structures of proteins

Deamination

taking N group off of the amino acid-end up with ammonia (toxic) can come from foods and tissue amino acids. The gut bacteria will hydrolyze urea. Most of it will go to kidney for excretion through the urine. Some of it will leak back into the intestine, bacteria in intestine hydrolyze it, you get 2 N and CO2. The ammonia goes back to the blood and back to the liver.

Excess or a large amount of protein is consumed 

Amino acid catabolism via transamination in muscle produces

70

= 20 grams from intestinal enzymes and 50 grams from intestinal cells.

Small amouths of ammonia continuously enters the blood from tissues throughout the body. The ammoia is primarily removed from the blood by the ___ to prevent the person will go into a coma.

Deamination

Stomach, gastrin, pepsinogen

Protein catabolism

Excess amino acids, the amine group is taken off. That nitrogen is toxic if it builds up, largely disposed off via urea. The synthesis occurs in the liver, excretin ooccurs via the kidney. Some urea cycles to the intestine where microorganisms hydrolyze the urea and then amonnia comes back

The ketoacids is amino acids - amine group. Those excess amino acids get catabolized (liver)used for energy, some gluconeogenic, very few synthesize fatty acids. The liver is the key site for amino acid catabolism. with the exception for 3 amino acids: lucine, isoleucine, valine- the liver does not have the enzymes to cause transamination of those. They are metabolized in skeletal muscle. up to 50% of energy that the liver derives is from catabolism of excess amino acids. Transamination is one of the key enzymes involved in catabolism of amino acids. Transamination is involved in synthesis of dispensible amino acids. 

HIV/AIDS

Most of the nitrogen you eat as a protein is excreted in urine as

 Amino acid catabolism via deamination in muscle ultimately produces ___ in muscle.

Enteral formulas often contain the amino acid ____ to help maintain gut mucosal epithelial barrier and to help prevent multiple organ failure.

Branched chain amino acids are catabolized primarily in _____.

.         

Which age group needs the highest quality protein to allow normal protein metabolism?

Which two amino acids cannot undergo transamination to any appreciable extent and are thus totally indispensible?

Lysine and threonine

Certain amino acids are referred to as "nonessential"because the body can synthesize them

When blood ammonia concentrations are within normal levels and glutamate concentrations in the brain are normal, the brain removes any ammonia that enters the nerve cell by synthesizing

 Even when high protein diets are consumed (3-4 times the RDA), the amount of amino acids in the blood and cells are maintained at an upper limit by

increasing the activity of enzymes that catabolize amino acids. 

Valine, Leucine, Isoleucine

Which of the following is true in relation to degradation vs. synthesis of protein during the life cycle?

When a person is immobilized, the initial respose that occurs is protein degradation exceeding protein synthesis.

CCK

Free amino acid carriers :

1. Peptides are transported into the cell along with H+

most peptides go into the blood as free amino acids

2. As H is pumped in, the pH is lowered. 

H is pumped back into the intestinal lumen in exchange for Na.

Requires ATP.

About _____of amino acids are used by the intestinal cell before they even get into the blood.

(ex. The gut has rapid cell division and synthesis. CCK and Secritin synthesis. Apo lipoproteint B48)

• 10 grams are used per day by the gut and 10 grams are used by the immune system.
• Some comes from the diet, but alot is synthesized in the skeletal muscle.
  
• Important in the health of the intestinal cell.
• May reduce the risk of infection.
• Important in energy-forms ammonia and glutamate, alanine cycle (occurs in gut or muscle)

Glutamine

Lysine is a substrate for carnatine

Leucine, Isoleucin, Valine

 20-30%

Glutamine is the most abundant free amino acid in the body (glutamate + nitrogen= glutamine)

Important in carring Nitrogen out of the body. 

Glutamine in the kidney is an important transporter in Nitrogen in an acid environment where glutamine will be taken up by the kindney and a deaminase will remove the ammonia. Acid conditon will form ammonium. Ammonia will go into the filtrate and come back into the blood. Ammonium cannot.

The urea synthesis would be diminished some and more nitrogen would be carried by glutamine to help in terms of buffering pH

Some Carnasine is synthesized in the kindey

Carnasine can supply the blood with histadine.

Also found in foods (meat products)

A peptide that can be absorbed in tact. 

Arginine is synthesized in the kidney.  It can leave the kidney. Important in the urea cycle. 

Skeletal Muscle

Branch chain amino acids initial metabolism

synthesis of alanine and glutamine in muscle as a way to carry N from the muscle to liver

 Creatanine(spontaneous biprodcut of creatine metabolism) measure of muscle content because creatanine is excreted in the urine, it is not metabolized

3-methyl histidine is in lots of proteins, but actin once histidine is put into the peptide chain is methalated. When actin is degraded (turns over) amino acids are released and not catabolized, it is lost in the urine- indicator of muscle protein turnover

The brain has a very active system for taking up amino acids. Tyrosine Tryptophane is the substrate for transmitters. Tryptophane for seratonin. Tyrosine for norepniphrine & dopamine. Not much glutamate, glucose can synthiesze. Glutamine is the main way that nitrogen is released from the brain.

Tryptophane-melatonin involved in sleep cycle

Glutamate is a neurotransmitter and can produce GABA

Can produce neuropeptides

Tyrosine can come from diet or phenylalanine

Taurine is a substrate for

Tryptophane is a substrate for

Protein and energy requirements

0-6 months old ____cal/kg & ___grams protein/kg/day

Body building

Muscle loses phenylalanine 

Excercise increases protein synthesis

Recovery from Protein Energy Malnurition:

40

(need really good quality protein)

Burns, Surgery, Sepsis

Nitrogen balance

(tends to overestimate true retention)

If intake is greater than excretion then one is retaining nitrogen 

(ex. athletic training-muscle building)

After a meal:

Increase in protein synthesis

Decrease in protein catabolism

 (Net retention)

Increase in protein catabolism

Decrease in insulin

Negative protein balance

Several day of fasting- one would lose around 12 grams of nitrogen per day. Because of increased need for amino acids for gluconeogenisis.

Longer term starvation (2 weeks)  the adaptations that cause a loss of 3 grams of nitrogen per day. Because of increase in ketogenesis and then lower gluconeogenisis.

.80

Pregnancy requirements are ____grams/kg/day

The RDA is ____grams/kg/day.