Practical B

Question 1

Purpose of transamination

Answer 1

Interconvert aa’s and oxoacids with the aim of changing the amino group to aspartate for excretion -> carbon chains from ketoacids can be used as metabolic fuels

Question 2

Transaminases

Answer 2

Enzymes which transfer amino group from alpha aa to a 2-oxo acid -> most amino groups funnelled to aspartate or glutamate

Question 3

Pyridoxal phosphate

Answer 3

Tightly bound cofactor for transferases- from Vit B6

Question 4

Transaminases have keq.

Answer 4

Close to 1

Question 5

Pyruvate + glutamate ->

Answer 5

Alanine + 2-oxoglutarate

Question 6

Glutamate dehydrogenases use X as a co-enzyme

Answer 6

NAD(P)+

Question 7

Glutamate dehydrogenase catalyses

Answer 7

Reversible inter-conversion of glutamate to α-ketoglutarate and ammonia

Question 8

Toxic ammonium ion is transported

Answer 8

to liver where converted to carbonyl phosphate which enters urea cycle

Question 9

DNPH

Answer 9

• produces yellow colour of oxo-acids

- reacts with free oxo-acid group to form a hydrazone

Question 10

How does ninhydrin produce purple colour?

Answer 10

Ninhydrin reacts with the amino group of the free amino acid which upon further decarboxylation and removal of an aldehyde produces an adduct which forms a purple complex with another molecule of ninhydrin.

Question 11

Types of solvent mixture:

Answer 11

Silica gel, Al2O3, Cellulose

Question 12

Compare solvent systems for amino acids and oxo-acids

Answer 12

aa - higher in ammonia and ethanol

oxo-acids - higher in n.butanol

Question 13

Glutamate + Oxoloacetate ->

Answer 13

a- ketogluterate + Aspartate