Amino Acid Oxidation & Urea Cycle Flashcards
T/F the use of amino acids as fuel varies greatly by organism
True !
Describe how dietary protein is enzymatically degraded
- GASTRIN hormone released
- causes Parietal to release HCL
- causes chief cells to release : PEPSINOGEN
- pepsinogen converted into PEPSIN - Low PH triggers SECRETION HORMONE
- secretion hormone stimulates pancreas to release bicarbonate - CHOLECYSTOKININ secretes
- trypsinogen
- chymotrpsin
- procarboxypeptidase - ENTEROPEPTIDASE converts trypsinogen to trypsin
trypsin converts zymogens to active form:
- trypsinogen —> trypsin
- chymotrypsinogen —> chymotrypsin
- procarboxypeptidase A & B –> Carboxy Peptidase A & B
What do parietal cells release
HCL
what do chief cells release
Pepsinogen
low PH in the small intestines trigger release of what hormone
secretion
secretion hormone triggers release of what from the pancreas
bicarbonate
what converts trypsinogen to trypsin? and once trpysin is formed what happens
enteropeptidase converts trypsinogen to trypsin. trypsin converts zymogens to their active form
what is occuring in acute pancreatitis
zymogens are getting converted into their active form . Clearly the pancreatic trypsin inhibitor is not working because it should protect the pancreas from getting affected by a protease
what 3 zymogens are present in the pancreas
trypsinogen
chymotrypsinogen
procarboxypeptidase
the less toxic form of ammonia is called
urea
Breifly describe what happens to an amino acid when it gets broken down
the NH4 goes thru the urea cycle and the the carbon skeleton goes through the citric acid cycle and can eventually go thru gluconeogeneisis.
what does ammonotelic mean
secrete ammonia
what does ureotellic mean
secrete urea
what does uricotellic mean
secretes urea and ammonia
amino groups form many amino acids are collected in the form of ______ in the liver
glutamate
where does oxidative deamination occur
in the mitochondrial matrix of the liver
what enzyme is needed for oxidative deamination
glutamate dehydrogenase
what are the negative and postive regulators of glutamate dehydrogenase?
- is GTP
+ is ADP
Where does the urea cycle occur
it occurs in 2 compartments of the liver cell.
- Liver mitochondria
- Cytosol
where does the feeder step of the urea cycle occur
in the mitochondrial matrix
what is the rate limiting step of the urea cycle
the feeder step
what are 4 important enzymes for the urea cycle
ornithine transcarboxylase
arniginosuccinate sythase
arginosuccinase
arginase
what does the krebs bicycle refer to
pathway linking the urea cycle with the citric acid cycle
what is the name of the feeder enzyme for the urea cycle
cabamoyl phosphate synthase 1
under what kind of conditions would we see a highly active urea cycle
high protein diet, starvation when protein being broken down for energy
what is a positive regualator of cabormyl phosphate synthase 1
n acetylglutamate
what are the 2 fates of a carbon skeleton
ketogenic amino acids or glucogenic amino acids
what do ketogenic amino acids yield
convert to ketone bodies, yield acetyl coa
carbomyl phosphate synthetase 1 disorder will cause
+ ammonia
ornithine transcarbamylase disorder will cause
+ ornithine, + uracil, + orotic acid
arginosucuccinic acid synthetase disorder will cause
+ citruline
arginosuccinase acid lyase disorder will cause
+ citruline , + arginosuccinc acid
arginase disorder will cause
+ argine
pernicious anemia is caused by
B12 deficiency , folic acid deficiency , premature erythrocytes
What 2 tissues are important for diagnosis of heart and liver damage caused by heart attack ?
ALT GPT, AST, GOT
Why are urea disorders dangerous
nitrogen accumulates in the form of ammonia which is a highly toxic substance if not removed from the body
a urea cycle disorder is an example of what kind of disorder
inborn error of metabolism
what 2 aromatic amino acids are given to help with urea disorders
the aromatic amino acids benzoate and phenulbutyrate are given which combine with glycine and glutamine and are excreted in urine . ammonia is used to replenish the loss of these amino acids
2 examples of ammonia scavenging medications are
bezoate and phenylacetate
PKU is caused by lack of
phenylanine hydroxylase
Tyrosinemia II is caused by lack of
tryrosine aminotransferase
Tyrosenemia III is caused by lack of
p hydroxyphenylpyruvated dioxygenase
alkaptonuria is caused by lack of
homogentisate 1,2, dioxygenase
tyrosenemia is caused by lack of
fumarylacetoacetase
a build up of phenylalanine and phenylpyruvate can lead to what kind of symptoms
intellectual deficits
how is PKU controlled
limiting dietary intake of Phe
T/F degradation of branched chain amino acids occurs in the liver
false ! it does not occur in the liver. it happens in muscle, adipose tissue, muscle , kidney and brain
what enzyme is defective in maple syrup urine disease
branched chain a keto acid dehydrogenase complex
