Protein Flashcards
In the Stomach, how is protein digested?
Gastric parietal cells release HCL
- hCL disrupts protein structure
- Converts pepsinogen to pepsin
What is the function of pepsin?
It cleaves peptide bonds within and distant from the ends of a polypeptide chain to form large polypeptides and oligopeptides
What is used in protein digestion in the small intestine?
Cholecystokinin (CCK) and secretin
Where is CCK and secretin synthesized in and in response to what?
The duodenum in response to acid chym
What does CCK and secretin trigger?
Trigger pancreatic acinar cells to secrete bicarbonate, electrolytes, water, and digestive proenzymes such as:
- Trypsinogen
- Chymotrypsinogen
- Procarboxypeptidases
Where is Enteropeptidase secreted from?
Secreted from glands in duodenum
What does Enteropeptidase activate?
The conversion of trypsinogen to trypsin
What does Trypsin activate?
Converstion of Procarboxypeptidase to carboxypeptidase
Converstion of Chymotrypsinogen to chymotrypsin
What are the essential amino acids?
TV TILL PM and Histidine Tryptophan Valine Threonine Isoleucine Lysine Leucine Phenal Methionine
What are examples of non-essential amino acids and how are they synthesizes in vivo?
Cysteine made from methionine
Tyrosine made from Phenylalanine
How are amino acids absorbed?
Amino acids are absorbed mainly in the proximal small intestine via paracellular transport or via amino acid transporters
How are peptides absorbed?
Absorbed via PEPT1
What is the primary system the body uses to absorb AA?
PEPT1; we do not need to break them down all the way. They are absorbed much quicker this way.
What kind of transporter is PEPT1?
A cotransporter
What organs help regulate amino acid homestasis?
Intestine and kidney
Why is taking protein supplements (powder) such as glutamine bad?
Because it saturates the transporters and does not allow the transporters to take in other AA. Could end up with lower levels of other AA
Where is protein in the body?
Mostly in the skeletal muscle
Blood and Skin ~15%
Remainder in other tissues liver kidney brain lung
About 50% of all the protein in your body can be represented by what proteins?
Myosin (muscle)
Actin (muscle)
Collagen (skin)
Hemoglobin (blood)
What are the functions of proteins?
Major functional and structural component of every cell in the body.
- Enzymes
- Transport proteins
- Hair, fingernails, keratin, collagen
Protein by weight is mainly 16% what?
amino nitrogen
The objective of protein catabolism/metabolism is what?
To get rid of the nitrogen by going through transamination, deamination, and then urea excretion.
After protein is metabolized/catabolized what is left and what do you use it for?
A carbon skeleton and it is used to for energy by oxidizing it.
Which vitamins are needed for AA oxidation?
Pyridoxine (B6)
B12
Biotin
What vitamins are needed for AA interconversion?
Pyrodoxine (B6)
B12
Folate
What is the first step of AA catabolism?
To get rid of the nitrogen by transamination
What is the protein transamination mechanism that B6 is involved in?
amino acid loses nitrogen and forms a alpha keto acid. nitrogen is then excreted in urine.
aminotransferase is the enzyme involved.
What type of anemia occurs in B12 def?
Megalloblastic anemia
What AA would you measure to determine that someone has megaloblastic anemia.
Plasma Methionine levels. Low in people who have megaloblastic anemia (B12 def)
What AA is needed for collagen formation?
Ascorbate
What are the vitamin c (ascorbate) dependent enzymes needed for collagen synthesis?
- Prolyl-3 hydroxylase
- PROLYL 4 HYDROXYLASE
- Lysyl hydroxylase
What do studies say about protein and enhacing muscle mass?
studies show that increased protein combined with regular heavy resistance exercise can enhance muscle development relative to training alone.
If you want to gain muscle mass you should have a protein intake of what?
1.8g/kg
Is there any effect on increasing muscle mass if you take in about 2.4 g.kg of protein? (triple RDA)
NO. platuea
What are the two proteins in milk that are great for building muscle?
Whey and Caesin
You should take caution what what kind of protein supplements?
Individual amino acid supps.
