What can the 7 intermediates produced from the aa be subdivided into
- Glucogenic: TCA cycle intermediates that can be shunted to gluconeogenesis
- Ketogenic: AcetylCoA derivates that can be used for ketone body synthesis.
18/20 aa are at least partially______. 4/20 glucogenic and ketogenic products include ____2/20 are purely ketogenic.
glucogenic. 3 aromatics + Ile; Leu and Lys
Methionine breaks down into ____. Phenylalanine breaks down into ______
cysteine; tyrosine
The key to interconversion of aa & carbs lies in the interrelationship between aa and:
alpha keto acids
What are the 7 metabolites of aa metabolism in glucogenic and ketogenic
Glucogenic:
- pyruvate
- oxaloacetate
- alpha KG
- fumerate
- propionylCoA
Ketogenic:
- acetoacetyl CoA
- acetylCoA
Which aa form into pyruvate
- Alanine
- Serine
- Cysteine
- Tryptophan
3C aa form a 3 C alpha keto acid to make
pyruvate
What are the 4C aa that are metabolized to make oxaloaceate
- Asparagine
2. Aspartate
What are the 5C aa that are metabolized to make alpha keto Glutarate
- Glutamine
- Proline
- Argenine
- Histidine
- Glutamate
Which branched chain aa make up succyinyl CoA and acetyl CoA
- Ile
- Valine
- Leucine
Valine gets converted to propionyl CoA which means its strictly
glucogenic
Ile gets converted to propionylCoA + acetylCoA which means its both:
glucogenic and ketogenic
Leu gets converted to acetoacetate which means its strictly
ketogenic
Branched chain aa share the first steps of:
oxidation. Get transaminated via branched chain aminotransferase
Which aa make up succinylCoA
- Methionine
2. Threonine
Breakdown of methionine produces:
cysteine
Met & Thr yield alpha keto butyrate that is converted to
propionylCoA.
PropionylCoA gets converted to:
succinylCoA
What does methlmalonyl CoA mutase need
cobalmin (B12)
What is munechausen syndrome by proxy
making people get purposefully sick to get attention
What are the two aa that are stricly ketogenic
Lycine and leucine
Which aa make acetylCoA
leucine and lysine
what aa make fumarate and acetylCoA
aromatic aa:
- Phe
- Tyr
- Trp
aromatic aa are both glucogenic and
ketogenic
What enzyme is required in Phe metabolism. What can result when you have deficiency of this enzyme
phenylalanine hydroxylase. PKU
What is the enzyme needed in homogentisate
homogentisate 1, 2 dioxygenase. Alkaptonuria can result if deficient.
what is PKU
- autosomal recessive disease
- deficiency in phenylalaline hydroxylase
- all newborns tested at birth
- treatment req low phenylalaline diet until adolescene
- lack of treatment results in severe mental retardation.
What is a cofactor in many hydroxylase reactions.
Tetrahydrobiopterin. IMportant for neurotransmitters.
what does alkaptonuria cause
pigment buildup throughout the body and arthiritis like symptoms.
a deficiency in what enzyme results in albinism
tyrosinase
In humans what is glycine converted to
CO2 and NH4
In liver, what can serve as a substrate for lactate dehydrogenase and gets converted to oxalate
glyoxylate
what is the major component of kidney stones
Calcium oxalate
which aa are both glucogenic and ketogenic
3 aromatics: Phe, Tyr, Trp
1 branched chain: Ile
Which 2 aa are strictly ketogenic
leucine and lysine
What are inborn errors of metabolism
- PKU: defect in phylalanine hydroxylase
- Alkaptonuria: defect in homogentisate oxidase
- maple syrup urine disease: defect in branched chain amino acid DH
- methylmalonic acidemia: defect in methylmalonylCoA mutase
- Homocystinuria: defect in cystathione synthase
How do you screen for inborn errors of metabolism
- carrier status: preconception testing of parents
- pre-implantation: test IVF embryos prior to implantation
- Pre natal: Chorionic villus (10-12 week of pregnancy), amniocentesis (15-18 week of pregnancy) cordocentesis (after 17th week of pregnancy)
