Amino Acid Metabolism Flashcards
What is creatinine?
A breakdown product of creatine and creatine phosphate.
What conditions lead to mobilisation of protein reseveres?
Occurs during extreme stress, such as starvation and is under hormonal control.
What affect does insulin have on protein metabolism?
Decreases protein degradation and increases protein synthesis.
What effects to glucocorticoids have on protein metabolism?
Increase degradation and decrease synthesis.
What are the two classes of amino acids?
Glucogeneic amino acids (used for gluconeogenesis) and ketogeneic amino acids (used for the production of ketone bodies)
Name a glucogeneic amino acid.
Alanine, glycine
Name a ketogenenic amino acids.
Lysine, leucine
What are the two processes by which nitrogen is removed by amino acids ?
Transamination and deamination.
What does the process of tramsamimation consist of?
Amino acid 1 + keto acid 2↔️amino acid 2+ keto acid 1
What are the most common enzymes involved in transanimation?
Amino transferase enzymes, which produce glutamate from a- ketoglutrate. As aspartate amino transferase. Which produces aspartate from oxaolactetate
What are the tow clinically significant amino transferase enzymes and why are they clinically significant?
Alanine aminotransferase )ALT) and aspartate amino transferase (AST) , which are used as a measure of liver function.
What are so,e key features of the urea cycle?
5 enzymes involved, a high protein diet induces enzyme levels and a low protein diet suppresses enzyme levels.
What is refeeding syndrome?
A condition caused by suppressed enzymes in malnourished patient causing an increase in ammonia levels due to a reduced function of the urea cycle
What are the key enzymes involved in deamination?
Amino acid oxidases, glutaminase, glutamate dehyrogenase
How is ammonia transported in the blood?
With alanine, (amine group is combined with pyruvate) and as part of glutamine (amino group is combined with glutamate)
How are defects in the urea cycle often inherited?
Autosomal recessive genetic disorders.
What are two clinical problems of amino acid metabolism?
Homocysteniuria and phenylketonuria.
What is phenylketonuria?
A deficiency of phenylalanine hydroxylase which leads to an acclulmation of phenylalanine, and is autosomal recessive with the affected gene on chromosome 7.
What is homocystinuorias?
Co,,only a defect in the cystathoine B-synthase enzyme, which leads to issues breaking down methadone in the body and causes an acclamation of homocysteine in the tissues….
What is a positive nitrogen balance and when is it evident?
When protein intake>output, and occurs during growth, pregnancy, and recovery from malnutrition .
