BIOC192 Lecture 31 - Oxidation of Amino Acids

Question 1

what 2 things does deamination generate?

Answer 1

1) a carbon skeleton

2) a free amino group

Question 2

what can a carbon skeleton be used for?

Answer 2

can be used for energy capture in catabolic reactions

Question 3

what is the result of the production of a free amino group?

Answer 3

the free amino group is generally excreted

Question 4

what ways can deamination occur?

Answer 4

• some amino acids can be deaminated by releasing their amino groups to solution
• transamination. reaction where the amino acid is deaminated by transferring their amino acid to a keto acid

Question 5

what are transamination reactions catalysed by?

Answer 5

catalysed by aminotransferase enzymes (transaminases)

Question 6

what is required for transamination reactions?

Answer 6

a co-enzyme called pyridoxal phosphate

Question 7

what is pyridoxal phosphate derived from?

Answer 7

derived from vitamin B6

Question 8

what does pyridoxal phosphate carry?

Answer 8

carries the amino group (from the amino acid to the keto acid)

Question 9

what are the forms of pyridoxal phosphate and how do they differ in amino acid groups?

Answer 9

1) pyridoxal phosphate (no amino group)

2) pyridoxamine phosphate (with amino group)

Question 10

how many steps are there in there in the transamination reaction?

Answer 10

involves 2 steps

Question 11

what occurs in the 1st step of transamination?

Answer 11

amino group is transferred from the amino acid to the pyridoxal phosphate to create pyridoxamine phosphate

Question 12

what occurs in the 2nd step of transamination?

Answer 12

amino group is transferred from pyridoxamine phosphate to the keto acid

Question 13

what are the amino acid/keto acid pairs in metabolism?

Answer 13

glutamate –> alpha-ketoglutarate
aspartate –> oxaloacetate
alanine –> pyruvate

Question 14

can keto acids feed into the metabolic pathways?

Answer 14

yes either directly into pyruvate and actyl-CoA or in the citric acid cycle

Question 15

what are the 2 ways keto acids can enter metabolic pathways?

Answer 15

1) some keto acids can enter directly

2) some keto acids require modification first

Question 16

what is the relationship between transamination reactions and nitrogen?

Answer 16

transamination reactions are also required to remove excess nitrogen via the liver

Question 17

what is oxidative phosphorylation?

Answer 17

the coupled process of electron transport through the electron transport chain (ETC) and the phosphorylation of ADP to ATP by ATP-synthase

Question 18

how are the processes of oxidative phosphorylation coupled?

Answer 18

coupled by a proton gradient made by the electron transport chain

Question 19

what uses the proton gradient?

Answer 19

ATP-synthase

Question 20

where is the electron transport transport chain located?

Answer 20

located in the inner membrane of the mitochondria