Lecture 15

Question 1

provides ~10% of our daily energy

Answer 1

amino acid catabolism

Question 2

two places that deal with nitrogen metabolism

Answer 2

liver and kidney

Question 3

the way we get rid of Nitrogen

Answer 3

urea!

Question 4

glutamate funnel

Answer 4

all AA come into the liver and dump nitrogens onto α-KG and → Glutamate

this is Transamination

rxn catalyzed by Amino Transferase

Question 5

amino transferase

Answer 5

enzyme that catalyses the transfer of amino groups to αKG

Question 6

Answer 6

α KG

Question 7

Answer 7

PLP

Question 8

PLP

Answer 8

Pyridoxal phosphate

Question 9

Role of PLP cofactor

Answer 9

allows transaminations by forming adducts to nitrogen and allowing the transfer with a keto acid

Question 10

oxidative deamination

Answer 10

going from amino group to ammonia

deamination of glutamate to regenerate αKG and free nitrogens

Question 11

glutamate dehydrogenase does

Answer 11

deaminates glutamate and regenerates αKG

Question 12

glutamine

Answer 12

also carry nitrogen and can be deaminated

(delivered form muscles)

Question 13

Alanine when deaminated..

Answer 13

generates pyruvate,

used to generate new glucose

Question 14

role of pyruvate and alanine in movement of nitrogen between muscle and liver

Answer 14

the deaminated ala produces pyr ⇒ used for producing new glucose.

essentially: flow of lactate & ala out of muscle into liver when glucose is needed

Question 15

key starting molecule in ornithine cycle

why?

Answer 15

urea!

becuase it is very stable, not very stable and have high pKA

very efficient in carrying nitrogen

Question 16

function of urea cycle

Answer 16

safe way to get rid of NH₃s

production of urine

Question 17

where does urea cycle occur?

Answer 17

between the mitochondria and the cytosol

Question 18

allosteric regulator of the rate limiting step in urea cycle

Answer 18

acetylglutamate synthase

Question 19

rate limiting enzyme of urea cycle

Answer 19

Carbamoyl phosphate

Question 20

essential amino acids are

Answer 20

amino acids that we cannot make and thus must consume:

Question 21

One carbon metabolism cofactors: overview of function

Answer 21

Biotin: activates single carbon CO₂ to add to things

Tetrahydrofolate: useful in dropping methy group on other AA

S-Adenosinylmethionine: methyl group donor

Question 22

starting product for NADP

Answer 22

nicotinate (niacin)

Question 23

PKU

Answer 23

phenylketourea: a deficiency in pathway of converting phenylalanine to tyrosine

Question 24

PKU as prototype AA catabolic disease

Answer 24

deficiency in these enzymes leads to buildup of substance like phenylalanine. People can’t process things in diet

Question 25

3H₂ + N₂ → 2NH₃

Answer 25

Nitrogen fixation

Question 26

nitrogenase funtion

Answer 26

(enzyme) fix nitrogen in the atmosphere

Question 27

interplay between legumes and nitrogen fixing bacteria

Answer 27

legumes provide food for bacteria and bacteria fix nitrogen for the legume. symbiotic relationship

Question 28

Anammox bacteria

Answer 28

**Anaerobic ammonium oxidizing bacteria** do nitrogen fixation without the prescence of O₂ *ammonia → nitrogen* with the help of hydrazine (fuel!)

Question 29

hydrazine is

Answer 29

one of the best fuels, very reactive

Question 30

organelle unique to annamox bacteria to contan hydrazine

Answer 30

Anammoxosome coated by ladderane lipids (look like ladders) creating and intert chanber to hold hydrazine

Question 31

Ladderane lipids

Answer 31

hydrocarbons that make up the hydrazine-proof chamber in annamox bacteria. they are only seen in these bacteria

Question 32

common route for nitrogen in mammals

Answer 32

N₂→NH₄+ →NO→ NH₄+ in AA →(diet) conversion to needed compounds

Question 33

collection of enzymatic activities

Answer 33

nitrogenase

Question 34

nitrogenase at the heart of N₂ fixation

Answer 34

very sensitive to O₂, exergonic process.

Question 35

Rhizobia

Answer 35

is a bacteria that does N₂ fixation rxns by attaching to the roots of the legumes (organelle like) = simbiotic relationship between the plant and bacteria

Question 36

Leghemoglobin

Answer 36

A legume-specific special version of hemoglobin, which binds to O₂ and sucks it out of the solution to protect the Rhizobia

Question 37

importance of glutamine in nitrogen anabolism

Answer 37

The synthesis of glutamine helps get NH₄+ into metabolism

Question 38

regulation of glutamine synthetase done by

Answer 38

**Adenylation** 2 layers of regulation: one from AMP addition which is regulated by UMP covalent modification

Question 39

2 layers of regulation of glutamine synthetase

Answer 39

uridylylation regulates adenylylation

Question 40

amino acids are synthesized form ______ and \_\_\_\_\_

Answer 40

Krebs Clycle and Pentose phosphate patway