Amino Acid Catabolism Flashcards
What is our source of amino acids?
Proteins in our diet
Are there any storage mechanisms for amino acids?
No
What are the three roles of amino acids in metabolism?
Involved in the synthesis of proteins, metabolised to generate energy and converted to small active molecules.
What does decarboxylation do?
Removes a COOH in the form of a CO2
What does transamination do?
Takes an amino acid and an a-keto acid and swaps the amine and keto groups to form new molecules.
What is a non-specific transaminase?
A transaminase that isn’t specific to a particular amino acid
What are specific transaminases?
Those that are specific to a particular donor amino acid and are named after them
What is the most important non-specific transaminase?
Glutamate transaminase
What does deamination do?
Removes an amine group
What are the two types of deamination?
Oxidative and non-oxidative
What is the difference between oxidative and non-oxidative deamination?
Oxidative requires NAD+ and FAD whereas non-oxidative does not.
What are the two ketogenic amino acids and how do you remember them?
Lucine and Lysine, only two that start with L
What are the four ketogenic and glycogen of amino acids and how do you remember them?
Phenylalanine, isoleucine, tryptophan and tyrosine; PITT
What happens when the body comes into contact with ammonia?
Ammonia attaches to another molecule to create an amino acid and is then expelled by the urea cycle
Where does protein digestion occur?
In the stomach and small intestine.
What do proteolytic enzymes do?
Degrade proteins by breaking peptide bonds
What are the two types of preteolytic enzymes?
Endopeptidases and exopeptidases
What is the difference between endopeptidases and exopeptidases?
Endopeptidases break bonds from the interior of the chain whereas exopeptidases break bonds from the terminal ends of the chain.
What does pepsinogen do?
When activated (pepsin) it cleaves COOH
What is stomach digestion limited by?
Contact time and specificity of pepsin
What is the digested stomach mix called?
Chyme
What two polypeptide hormones does chyme cause the release of?
Secretin and cholecystokinin
What is the difference between amino acids and carbohydrates/lipids sourced from our diet?
We can’t store amino acids.
What is the fate of active amines produced from decarboxylation of amino acids?
They are used to generate hormones and neurotransmitters
What happens to the a-keto acid after transamination or deamination?
It is metabolised to generate energy.
How are zymogens activated?
The enzyme enteropeptidase which is produced in the small intestine
