Urea Cycle Flashcards
What does glutamate synthase transfer to a-ketoglutarate?
Nitrogen
Glutamine is the ____ carrier.
Nitrogen
What are the three fates of ammonium?
Glutamate dehydrogenase
Glutamine synthase
Carbamoyl-phosphate synthase I
What happens in the reactions containing glutamate dehydrogenase and glutamate synthase?
Reductive amination of a-ketoglutarate to form glutamate
What happens in the reaction containing glutamine synthetase?
ATP-dependent amidation of gamma-carboxyl of glutamate
What happens in the reactions containing carbamoyl-phosphate synthase I?
2 ATP are required
1 activates bicarbonatem which the other phosphorylates carbamate
Why would the body want to have NH3 when it could be the more relevant NH4+?
NH3 is the form that can cross cell membranes
What is the breakdown of animo acids from food called and how does it work?
Transamination
Swap NH3 group for a different keto-acid
What is transamination?
Transfer of an amino group from an a-amino acid to an a-keto-acid
In amino acid biosynthesis, the amino acid glutamate is transferred to various _____ which generates _____.
a-keto acids, a-amino acids
What two amino acids are generated in mino acid catabolism?
Glutamate or aspartate
What are the essential amino acids?
Histidine, Isoleucine, Leucine, Methionine, Phenylalanine, Threonina, Tryptophan, Valine, Lysine
What is nitric oxide?
NO is a gas hormone which can diffuse into cells and is a messenger that activates guanylyl cyclase (cGMP synth)
What is NO synthesized from?
Arginine
What are the actions of NO?
Relaxes blood vessels, lowers blood pressure and is a neurotransmitter in the brain
What is converted into NO to dilate coronary arteries?
Nitroglycerin
When the body is in starvation, what are degraded to amino acids for glucose?
Proteins
What are the glucogenic animo acids?
Ala, Ser, Cys, Thr, Trp, Asp, Arg, Phe, Ile, Met, Val
What are the ketogenic amino acids?
Ile, Leu, Thr, Trp, Leu, Lys, Phe, Tyr
What process does the muscle eliminate nitrogen to replenish energy?
Indirectly due to the exchange of glucose and alanine
Which types of animo acids are the first to be catalyzed for these pathways?
Branched-chain (Leucine, Valine and Isoleucine)
Which intermediate of amino acid breakdown also is used in the formation of ketone bodies?
HMG-CoA
In the study of branched-chain amino acids, what is the key to understanding the relationship between dietary protein and carbohydrates?
Understnading the relationship between branched-amino acids, insulin and glucose metabolism
What is a major gluconeogenic amino acid and what happens to it when it enters the liver?
Alanine and it becomes urea
