Lecture 10

Question 1

What does Kinase do? and give an example

Answer 1

Catalyses the phosphoryl transfer from one molecule to another. Usually from ATP.
Glucose + ATP –> Glucose 6 phosphate + ADP

Question 2

What does phosphorylase do? and example

Answer 2

Catalyses the covalent addition of inorganic phosphate to a molecule.
Glycogen to Glucose 1 phosphate

Question 3

What does phosphatase do? and example

Answer 3

Catalyses the cleave of a phosphate to give a product without the phosphate.
Example G6P to Glucose in the ER lumen

Question 4

What does Mutase do? Example

Answer 4

Catalyses the shift of a phosphoryl group from one atom to another within the same molecule

Question 5

Whats the structural difference between phosphoglycerate mutase in yeast and in bacteria?

Answer 5

In yeast the form is tetrameric

In bacteria the form is dimeric and uses Mn2+ as a cofactor

Question 6

Isomerase does what and give an example

Answer 6

Isomerase catalyses the conversion of one isomer to another.

Triose phosphate isomerase, catalyses step 5 of glycolysis

Question 7

What does Hydratase do and an example

Answer 7

Catalyses the addition/removal of water. Enolase is a dimeric glycolytic enzyme.

Question 8

Enolase is an example of what type of enzyme and describe the active site of the enzyme, including the cofactors and residues

Answer 8

Example of hydratase.
2 Mg2+ cofactors
5 residues
His159, Glu168, Glu211, Lys345 and Lys396

Question 9

Synthase or Synthetase does what and example

Answer 9

Catalyses the synthesis of a product without the use of a high energy source
DHDPS catalyses the rate limiting and committed step in the lysine biosynthesis pathway in bacteria.

Question 10

What does catabolism involve?

Answer 10

Energy containing nutrients get turned into energy depleted products.
Carbs to Co2.
Uses ADP to ATP

Question 11

What does anabolism involve?

Answer 11

Precursor molecules to cell macromolecules.
Sugars to Polysaccharides.
Uses ATP to ADP

Question 12

What is NAD and NADH?

Answer 12

Nicotinamide adenine dinucleotide
NAD+ is oxidised form
NADH is reduced form

Question 13

What is FAD and FADH2?

Answer 13

Flavin adenine dinucleotide
FAD is oxidised form
FADH2 is reduced form

Question 14

What is sucrose?

Answer 14

Disaccharide

Question 15

What is glycogen?

Answer 15

Polysachharide

Question 16

Structure of glucose

a) What type of sugar?
b) How is the hemiacetal produced
c) what is the result after the hemiacetal
d) Glucose exists in how many forms and name each of these forms
e) Does it exhibit mutarotation?
f) Is it an anomeric carbon?
g) which form is most common and why?

Answer 16

a) Aldohexose
b) The CHO at carbon 1 produced a hemiacetal linkage with OH group at Carbon 5. Hydrogen from OH gets transferred to CHO with the double bond between CO being broken.
c) 2 Stereoisomers, alpha and beta
d) 3 forms. Open chain, alpha D glucopyranose and Beta D Glucopyranose
e) Yes
f) Yes
g) Beta due to less steric hinderence between the OH on C1 and OH on C2

Question 17

what is mutarotation?

Answer 17

Interconversion of alpha and beta anomers

Question 18

What is anomeric carbon?

Answer 18

Only C to be attached to two O’s

Question 19

How does Glucose get into cells?

Answer 19

Via GLUT transporters

Question 20

Name the tissue location of the following GLUTs and the types of uptakes

a) GLUT1
b) GLUT2
c) GLUT3
d) GLUT4
e) GLUT5

Answer 20

a) All tissues, basal glucose uptake
b) Liver and pancreatic B cells. Plays role in regulation of insulin in pancreas.
Removes excess glucose from blood in the liver
c) Brain, basal glucose uptake
d) Muscle and fat cells. Amount in muscle and adipose membrane increase with insulin signalling
e) Small intestine. A fructose transporter.