BMS07-1030 AA Metabolism Flashcards
What does an essential AA mean?
Its needed as a building block to make other AA
Can all AA be made?
No- out of 20 10 must be eaten
What’s a waste product from creatine?
Creatinine
What’s a waste product from purines/pyrimidines?
Uric acid
What is turnover?
Body proteins always being broken back down to AA
Name the 3 non-essential AA that we can make from keto acids and why are they important?
Alanine
Aspartate
Glutamate
Metabolism
Why is histidine essential?
For growth
Why is arginine essential?
If something goes wrong
What is the nitrogen balance? Why does this occur?
Nitrogen taken in from the diet should be equal to that excreted in various waste products
The rate of protein synthesis is equal to the rate of degradation
When is there a positive N balance?
N intake is greater such as in growth and pregnancy
When is there negative N balance?
In starvation or injury
How are cellular proteins removed?
Ubiquitin breakdown
What hormone can increase protein breakdown?
Cortisol
How are organelles removed?
Taken into vesicles which fuse with lysosomes
Deamination
AA + water + coenzyme(NADP) = keto acid + ammonia + coenzyme (NADPH)
What is a keto acid?
R-C-COOH
The middle C is double bonded to O
Transamination
AA + keto acid = keto acid 2 + AA 2
Coenzyme used
Using an aminotransferase enzyme
Which AA is used in transamination and why?
Glutamate as its the only one there’s an enzyme for (glutamate dehydrogenase)
What 2 things do AA break into?
Ammonia and a keto acid
Which part of the AA is removed to get a keto acid?
N bit
What do most AA become when loosing the amino group?
Keto acid
How can keto acids be used? (2)
Metabolised in the TCA cycle to carbon dioxide and water to make ATP
13 of them can be converted back to glucose by the liver (glucogenic)
What can leucine and lysine be degraded into?
Acetyl coenzyme A (ketogenic)
Which 3 AA are needed for urea synthesis?
Aspartate
Alanine
Glutamate
What is alanine used to make?
Pyruvate
What is transdeamination and where does this occur?
A mixture of transamination and deamination
Liver
What does the liver synthesis?
Haem
Purines
Pyrimidines
Plasma proteins
Which organ convert the amino groups to urea?
Liver
What are ammonia groups transported as in the blood stream?
Glutamine as it has 2 amino groups so carries them efficiently
What happens when glutamine is converted to glutamate?
Glutaminase
Water turns to ammonia
What happens when glutamate is converted to glutamine?
Glutamine synthetase
ATP and ammonia go to ADP and Pi
Which AA are important for transporting N between organs? (4)
Glutamate
Glutamine
Aspartate
Alanine
Why can ammonium ions be useful?
In the kidney for pH regulation
What is fumerate used for?
TCA cycle
In the urine cycle which AA makes urea?
Arginine
Which AA makes aspartate?
Citrulline
What AA does aspartate make?
Arginosuccinate
What is removed to form arginine?
Arginosuccinare has a fumerate removed
What converts ornithine to citruline? What forms this enzyme?
Carbamoyl phosphate loose a Pi, this is formed from carbon dioxide and ammonia and 2 ATP
What disease can ammonia cause?q
Cerebral oedema
What may cause an inability to convert ammonia to urea? (hyperammonaemia)
Liver failure Genetic defects (reduction in enzymes in urea cycle)
