Amino acids Flashcards
What element of the amino acid defines its structure?
R group
What is a peptide bond
COO- and H3N, amino acid sequence defines the primary structure of the protein
What are the two means though which the body is able to restore protein concentrations?
- digestion and absorption
- though protein degradation
What are the two pathways for protein degradation?
- Ubiquitin
2. Lysosomal degradation of enzymes
How big is the amino acid pool within a human?
amino acid pool is 500 grams
How does the ubiquitin pathway work, is it regulated and is it ATP dependant?
- ATP dependant pathway
- degradation of ubiquinated proteins in proteosomes
Explain how the lysosomal degradation of enzyme occurs, the degree of regulation and whether it is ATP dependant:
- Mostly independant of ATP
- internalised to lysosomes
- regulated
What must we do to an amino acid before it is useful?
need to remove amino- N before the carbon skeleton is useful for energy or gluconeogenesis
What are the entry points for carbon from amino acids?
- amino acids that increase TCA cycle intermediates
- amino acids that increase both TCA intermediates and acetyl CoA
- amino acids that just increase acetyl CoA
What are the two main enzymatic players that are involved transamination and direct deamination?
- transamination- occurs in all tissues, but mainly in the liver
- direct deamination- liver and the liver and kidney
What are the three transaminases that are in all tissues but mainly in the liver?
alanine transaminase
aspartate transaminase
glutamate transaminase
What are the enzymes that are involved in direct deamination?
glutamate dehydrogenase (liver) glutaminase (liver and kidney)
How do we get rid of ammonia, what is the name and the molecule and where is it transported to?
needs to be converted into urea, mad in the liver, transported in the blood and excreted through the kidneys
What is the energy cost of producing a molecule of urea?
4 ATP
Where does the nitrogen come from urea
one comes from oxidative de-amination (glutamate) whereas the other typically comes from transamination from aspartate
How is the urea cycle regulated?
enzyme induced by 20 fold by high protein and starvation
Where is urea cycle nitrogen sourced from?
glutamate
asparatate
glutamine
What is used to stimulate carbomoyl phosphate synthtase one allosterically?
N-acetyl glutamate
What is the name to the enzyme that is used to convert glutamate to glutamine and is ATP required or used?
ATP is used, glutamine synthetase
What is the name of the enzyme that is used to convert glutamine to glutamate?
glutaminase
What is another use for glutamine?
transports amino N to the kidney for the nitrogen to be disposed of directly
What is the precursor of glycine and the enzyme that is involved?
- serine is the precursors
- the enzyme that is involved is serine hyroxbmethyltransferase
What are the two main reasons for the high protein requirement of cats?
- Inability of enzymes involved in amino acid catabolism to adapt to changes in dietary protein intake
- Decreased capacity to regulate protein regulation
Do bos inducus cattle have low or high levels of the calpastatin protein?
high levels of calpastatin protein
