amino acid metabolism

Question 1

alpha amino acids

Answer 1

• consist of carboxylic group and amino functional group attatched to same carbon
• center carbon is alpha carbon
• R groups that differ amino acids from each other

Question 2

optical properties

Answer 2

• c atom w/ 4 distinct constituents is chiral
• glycine not chiral, has h
• all Aas in proteins has same sterc configuration

Question 3

degradation or synthesis of amino acids

Answer 3

transamination

Question 4

transamination

Answer 4

• transfer of amine group from one molecule to another
• catalized by enzymes called transaminases
• alpha ketoglutaric acid

Question 5

synthesis of new amino acis

Answer 5

• transamination
• alpha ketoglutaric acid use transamination of diff aa to make glutamic acid
• react with keto acid to make new aa

Question 6

nitrogen metabolism

Answer 6

• interconversion of alpha ketoglutaric acid and glutamic acid
• collection and recieving agent

Question 7

localization of transaminases

Answer 7

• ASAT=GOT in liver heart muscle

- ALAT=GPT in liver

Question 8

essential and non-essential amino acids

Answer 8

• transamination can be used t make new aas that are not present in diet
• keto root do not exist for 8 aas, they are therefor essential in diet
• non essential aas can be made by other processes than transamination

Question 9

metabolism of amino groups of aa

Answer 9

oxidative deamination

Question 10

oxidative deamination

Answer 10

• oxidative, occur under aerobic conditions in all tissue
• liver
• amino acid converted into corresponding keto acid by removal of functional amine group
• ammonia goes into urea cycle

Question 11

which molecule does oxidative deamination mainly occur on

Answer 11

• glutamic acid bc it is the end product of many transaminations

Question 12

glutamate dehydrogenase

Answer 12

• allosterically controlled by ATP and ADP
• ATP inhibitor
• ADP activator

Question 13

central role of glutamic acid

Answer 13

• most aas may be deaminated but has sifnificant reaction for glutamic acid
• trans-deamination: combo of transamination and deamination of glutamic acid
• recycling reaction for glutamic acid

Question 14

fate of carbon skeleton

Answer 14

• complete metabolism into co2 and h2o by cac
• converted into acetyl CoA can further be converted to ketone bodies
• if carbs lack from diet, pyruvic acid, OAC or molecule of cac can be converted into glucose or glycogen

Question 15

production of ammonia

Answer 15

• ox deamination: L-glu dehydrogenase, D-amino acid oxidases
• degradation of biogenic amines
• absorption from gi tract

Question 16

detoxification of ammonia

Answer 16

• urea cucle
• L-glu synthesis
• gln and asn synthesis
• in kidney: glutaminase activity, ammonium ion prod
• purine synthesis: uric acid

Question 17

species lacking urea cycle

Answer 17

• birds have no arginase enzyme - no urea cycle

Question 18

portosystemic shunt

Answer 18

• extrahepatic portosystemic shunt
  blood of portal vein eter in vena cava
• risk of ammonia toxicosis increase

Question 19

biogenic amine

Answer 19

• histamine - histidine carboxylase
• tyr->DOPA->catecholamines - dihydroxyphenylalanine decraboxylase
• tyr->tyramine - tyrosine decarboxylase
• trp->serotonin= 5-OH-tryptamine - 5oh tryptophane decarboxylase
• glutamat->bamma aminu butyrate - glutamate decarboxylase

Question 20

tauine

Answer 20

• essential for cats

- bile acids only conjugated by taurine to produce bile salts

Question 21

polyamines

Answer 21

• ornithine->putrescine

- Lys-> cadaverine

Question 22

cadaverine

Answer 22

foul smelling molecule produced by protein hydrolysis

Question 23

putrescine

Answer 23

• produced by breakdown of amino acids

Question 24

dipeptides

Answer 24

• carnosine

- anserine

Question 25

role of glutathione

Answer 25

• release H by oxidation

- released H is antioxidant, split s-s bonds of proteins

Question 26

antioxidant role of glutathione

Answer 26

• remives peroxides via glutathione peroxidase

- H2O2 from PPP