Biochem Of Met, Block 2, # 9 - Nitrogen Met: Amino Acids 1

Front 1

What percentage of human energy is derived from the oxidation of amino acids?

Back 1

10-15%

Front 2

The ketone skeleton: its degredation can lead to what two major pathways? what products are in those pathways?

Back 2

Can be gluconeogenic or ketoneogenic.

Gluconeogenic compounds include: pyrvate, alpha ketogluterate, succnyl co-A, fumarate, and oxaloacetate.

Ketoneogenic compounds: acetyl-CoA and acetoacetate.

Front 3

Alpha ketogluterate - what amino acids converge on this gluconeogenic intermediate?

What intermediate do they all first form?

Back 3

argenine
glutamine
histadine
proline

All first form glutamate.

Front 4

Argenine, glutamine, histadine, proline - what's the pathway to become gluteamte, and then alpha ketogluterate?

Back 4

Argenine and proline share a common intermediate.

Argenine uses arginase (seen before)

Histadine requires h4 folate

Glutemate requires Glutaminase

Glutemate becomes alpha ketogluterate through GLUTEMATE DEHYDROGENASE

Front 5

Succnyl CoA: what AA's become this?

What common intermediates are formed?

Back 5

MTVI: Methaonine, threonine, valine, isoleucine

All 4 pathways meet at PROPINYL COA, which becomes MethylMalonyl CoA, which becomes Succnyl CoA.

Front 6

How do methaonine, and threonine make the journey?

Back 6

Methionine and threonine share an intermediate: alpha ketoBUTYRATE.

Methionine has an early intermediate, HOMOCYSTEINE. Going from homocysteine to alpha ketobutyrate requires PLP cofactor and CYSTOTHIANINE beta SYNTHASE.


Threonine requires PLP to become alpha ketobutyrate

Front 7

What about valine and isoleucine?

When you've made propinoyl CoA, what happens?

Back 7

No intermediates necessary, but know that isoleucine can become both GLUCONEOGENIC and KETOGENIC.

After propinyol CoA, make methylmalonyl CoA.
This goes to succinyl CoA, requires cofactor B-12, and uses Methylmalonyl CoA Mutase.

Front 8

What disease states can be associated with this pathway?

Back 8

Deficiencies in both cistathionine beta synthase and methylmalonyl Co A mutase cause diseases.

Cistathionine beta synthase deficency causes HOMOCYSTINURIA

Methylmalonyl CoA deficiency causes Methylmalonic Acidemia

Front 9

What causes maple syrup urine disease?

Back 9

Inability to break down branched amino acids (leuine, isoleucine, and valine)

Front 10

What's the biggest methyl donor in the cell, what creates it, what enzymes are involved, and what disease state should we be thinking of?

Back 10

SAM (s-adenosyl methionine).

Greating SAM happens from breaking up methionine, using methionine adenosyl transferase

Creating methionine from homocistine requires METHIONINE SYNTHASE, which uses folate H4 AND b12 - so b12 deficeincy causes pernitious anemia.

Front 11

Asparagine and aspartate - what do they become and how?

Back 11

They form oxaloacetate. Note that asparagine and asparatate are related, that asparagine has 2 aminos and asparatate has 1. They are akin to glutamine and glutamate.

1st reaction - asparagine to asparate using ASPARAGINASE (like glutamine!)

2nd reaction - asparatate to oxaloacetate via ASPARTATE DEHYDROGENASE

Front 12

Pyruvate pathway: what AA's are involved?

Back 12

try ala thre gly serine cystine

tryptpophan alanine, glycine, serine, cystine.

Front 13

What pathways do our pyruvate forming amino acids go through?

Back 13

Tryptophan turns into alanine, alanine turns to pyruvate (via alanine aminotransferase).

Threonine donates part to become ACETYL-CoA (ketogenic), the rest becomes glycine. Glycine becomes serine (PLP required), serine becomes pyruvate (PLP required).

Cysteine becomes pyruvate all on its own.

Front 14

Things that break up into fumarate, acetoacetyl CoA, acetyl CoA< and succnyl CoA:

Back 14

PHE to tyrosine, which becomes fumarate and acetoacetyl CoA

Leucine becomes acetyl CoA

Isoleucine becomes acetyl CoA and succnyl CoA

Tryptophan becomes pyruvate and acetoacetyl CoA

Lysine becomes acetoacetyl CoA

Front 15

What diseases happen with PHE breakdown?

Back 15

PKU: phe to tyr uses phenylalanine hydroxylase.

ALkaotonuria - further breakdown of tyrosine, mistake in HOMOGENTINASE 1,2 dioxygenase.

Front 16

Some AA's can be either ketogenic or gluconeogenic. which are they?

which are exclusively ketogenic?

Back 16

Exclusively ketogenic: Leucine and Lysine.

Swing both ways:
Tryptophan, threonine, phenylalanine, tyrosine, isoleusine.
(I try trip phe three)