Lecture 25: Utilization of Amino Acids

Question 1

Amino Acid Catabolism

Answer 1

-breaks to NH3 and carbon skeleton

Question 2

Catabolism of amino acid carbon skeleton

Answer 2

-CO2 and water
-glucose
-acetylCoA
-ketone bodies

Question 3

glucogenic

Answer 3

-can be used for gluconeogenesis
-pyruvate
-TCA intermediates

Question 4

Ketogenic

Answer 4

-can be used for fatty acid synthesis or ketogenesis
-acetyl-CoA
-acetoacetyl CoA

Question 5

Glucogenic and ketogenic amino acids

Answer 5

-Ile, Thr, Phe, Tyr, Trp

Question 6

ketogenic amino acids

Answer 6

-Lys
-Leu

Question 7

Glucogenic amino acids

Answer 7

-not lys and leu but everything else

Question 8

Essential amino acids

Answer 8

-cannot be synthesized in sufficient amounts by body

Question 9

Nonessential amino acids

Answer 9

-can be made by body
-Ala, Asp, Asn, Glu, Ser

Question 10

Conditionally essential amino acids

Answer 10

-nonessential amino acids that require essential acids for synthesis
-Phe makes Tyr
-Met makes Cys

Question 11

a-keto acids

Answer 11

-amino acids without amine group
-some available as intermediates in glycolysis ot TCA cycle

Question 12

a-keto acids:

Answer 12

-alanine
-aspartate
-glutamate
-pyruvate
-oxaloacetate
-a-ketoglutarate

Question 13

Transamination

Answer 13

-removal of amine group from amino acid
-coupled with production of glutamate from a-ketoglutarate
-catalyzed by aminotransferases
-requires pyridoxal phosphate cofactor

Question 14

Hotseat

Question 15

Oxidative deamination by glutamate dehydrogenase

Answer 15

-removes amine group from glutamate by producing ammonia and NADH
-can catalyze reverse reaction with NADPH but ammonia too low under normal conditions for reaction to occur
-glutamate to a-ketoglutarate

Question 16

ammonia

Answer 16

released amine group of amino acid

Question 17

Oxidative deamination by amino acid oxidase

Answer 17

-removes amine group as ammonia
-not significant contribution to metabolism

Question 17

Glutamine

Answer 17

-ammonia transporter
-most abundant amino acid
-transported to intestines and converted to alanine and ammonia

Question 18

Alanine in the liver

Answer 18

-converted to pyruvate for gluconeogenesis
-converted to ammonia for urea

Question 19

Glutamine synthetase

Answer 19

-produces glutamine grom glutamate and ammonia
-requires ATP

Question 20

Flow of nitrogen

Answer 20

-amino acids to glutamate to ammonia
-glutamate to alanine to ammonia
-ammonia to glutamine to alanine
-alanine to ammonia to urea

-liver and skeletal muscles

Question 21

Glutamate metabolite

Answer 21

GABA

Question 22

tyrosine metabolite

Answer 22

-dopamine
-norepninephrine
-epinephrine

Question 23

tryptophane metabolite

Answer 23

-seratonin
-melatonin

Question 24

histidine metabolite

Answer 24

histamine

Question 25

glycine metabolite

Answer 25

oxalate

Question 26

y-aminobutyrate (GABA)

Answer 26

-from glutamate -inhibitory neurotransmitter -reduces excitability -negative change in membrane potential (hyperpolarization)

Question 27

catecholamine synthesis

Answer 27

-dopamine converted to norepinephrine and epinephrine in adrenal medulla

Question 28

parkinson's

Answer 28

not enough dopamine

Question 29

serotonin

Answer 29

-regulate mood, appetite, sleep, motility in GI tract

Question 30

Histamine

Answer 30

-allergic response -vasodilation -promote wakefullness -gastric acid release

Question 31

Oxidation of glycine

Answer 31

-results in oxalate -may lead to kidney stones -hyperoxaluria

Question 32

hyperoxaluria

Answer 32

-excessive oxalate production -most commons from diet -lack of enzyme converting glyoxylate to glycine