Amino Acids Flashcards
wk 10
can essential amino acids be synthesised in the human body?
no
What are nonessential amino acids formed from?
metabolic intermediates or from other amino acids
What are Glucogenic classification of amino acids?
Used to synthesise glucose (using TCA/ Pyruvate)
What are ketogenic classification of amino acids?
Make acetyl-CoA
OR used to synthesis ketone bodies or fatty acids
What is the classification of phenylalanine?
Amino acids that re both glycogenic and ketogenic
How is Nitrogen removed from the amino group so can enter the urea cycle?
removing amino group and transferring to a-ketoglutarate = glutamate
What does pyruvate becomes after transamination (in muscle cells after glycolysis)
Alanine
What occurs in the Glucose-alanine cycle?
Ammonium ion in muscle cells –> liver as alanine –> secreted eventually as urea.
What is the most important ammonia-forming reaction?
oxidative deamination of glutamate via GDH in the liver.
reversible (synthesis and degrades glutamate)
Where is Glutamine formed and what is its major role?
from glutamate using glutamine synthease
goes to liver, kidney and intestines
removes a N and transports it to the liver.
How are amino groups of amino acids turned into ammonia?
By transamination and oxidative deamination
What is the purpose of the Urea cycle?
removal of excess NH4+
What is the Net Reaction of the Urea cycle?
NH4+ + HC03- + asparate + 3ATP –> urea + fumarate + 2 ADP + 2Pi + AMP + PPi
How many molecules of urea are produced per urea?
4 ATP
What is the key regulator of the urea cycle?
CPS-I
What type of enzyme is CPS-I and when is it activated?
mitochondrial enzyme
activated by N-acetylglutanate when there are high levels of glutamate and arginine.
What does an overproduction of dopamine result in?
Schizophrenia
What does a genetic deficiency of phenylalanine Hydroxylase result in?
Phenylketonuria - mental retardation if not treated immediately after birth
What part of Nitrogen is toxic?
NH2
How can N be lost and what needs to happen?
Protein and nucleic acid degradation- needs to be replaced
