Lecture - Biochemical Synthesis 1 Flashcards Preview

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Flashcards in Lecture - Biochemical Synthesis 1 Deck (22):
1

Key biochemical species

- amino acids
- fatty acids

2

NEcesary precursors

- Purines
- Pyrimidines
- Ribose
- Cholesterol
- Porphyrins

3

Energy rich compounds for storage or export

- Fatty acids
- Ketone bodies

4

Providion of reducing power

- NADH
- NADPH
- Glutathione

5

DEtoxification and excretion

- Urea
- Mono-oxygenases
- glucuronidation

6

Biochemical species that cannot be synthesized

- Vitamins (except vit D)
- Essential amino acids
- essential fatty acids

7

Essential and non-essential amino acid

- Essential aa: required in diet, cannot be synthesized
- non essential aa: not required in fiet, synthezised from ingested precursors

8

Essential amino acids

- lysine
- histidine
- threonine
- methionine
- Phenylalanine
- Tryptophan
- Isoleucine, Leucine, Valine

9

Non essential amino acid

- Arginine
- Aspartate
- Glutamate
- Asparagine
- Glutamine
- Alanine
- GLycine
- Serine
- Cysteine
- Proline
- Tyrosine

10

Conversion of L-phenylalanine to L-tyrosine

- requires phenylalanine hydroxylase
- requires vitamine B

11

Synthesis of neurotransmitters from L-tyrosine

- tyrosine hydroxylase
- dopa decarboxylase
- dopamine b-hydroxyklase
- PNMT

- forms dopa then dopamine then norepinephrine and then epinephrine

12

Example of aa synthesis : Glutamate

- Glutamate can form a-ketoglutarate via the glutamate dehydrogenase enzyme

- glutamate is a precursor for several other AA: Glutamine, Proline, Arginine

13

Synthesis of FA: two important carriers

- coenzyme A
- Acyl carrier protein (ACP)

14

Synthesis of FA: the committed step

- when acetyl coA becomes malonyl co A (2C -> 3C)
- acetyl coA receives a carbon dioxide froup from bicabonate

15

Synthesis of FA: fatty acid dynthase complex

After malonyl coA, becomes condensed into 1C
- then a bunch of reductions forms butyryl ACP
- after butyryl ACP is formed, chain length increases by two carbons each cycle
- maximum chain length via Fatty acid synthase complex is 16C

16

3 ways to nomenclature fatty acid

- numbering from COOH: 1
- numbering from carbon after COOH: a,b,y,w
- Numbering from last carbon: w1, w-2...

17

Synthesis of longer chain FA and desaturation

- some very long chain FA required for membrane function
- desaturation: insertion of double bonds
- enzymes on cytoplasmic face of ER facilitate elongation and desaturation reaction

18

Cis vs trans fatty acid

CIS
- kinked
- natural form and major configuration in natuyre
- can synthesize ourselves, melting temp drops - more liquid

TRANS
- not kinked
- possible to make synthetically
- tend to pack and crystallize early

19

Essential fatty acids

- unsaturated FA with double bond beyoung C9
- desaturating enzymes cannot process this far from C1
- some essential fatty acids are required for synthesis of important biochemicals

N6- can be obtained in a wide variety of food
N3- more limited

20

Synthesis of cholesterol

- Acetyl coA -> Aetoacetyl coA -> HMG CoA -> Mevalonate

- statins inhibit HMG CoA to mevalonate : lower cholesterol but secondary effect include enhanced clearance of cholesterol rich lipoproteins

- Mevalonate -> C5 -> C10 -> C15 -> C30 (sqalene) -> C27 (cholesterol)

21

Synthesis of C10 and C15 is suppressed by biphosphonates

- but C15 is needed for protein prenylation (Ras) and Heme A (coenzyme Q10)

22

What is synthesized from cholesterol?

- steroids
- bile salts

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