Question

You are asked to determine the molecular weight of a protein in its unglycosylated state. What reagent should you add to the growth medium of the host eukaryotic cells to have the cells express the unglycosylated protein?

A.

Endoglycosidase H

B.

Endoglycosidase F

C.

Tunicamycin

D.

Nojirimycin

2.

You are asked to study a protein that gets targeted to the lysosomes in a host cell line. What molecular marker should you look for on this protein?

A.

GlcNAc-GlcNAc

B.

Gal ß 13 GalNAc

C.

Mannose 6-phosphate

D.

High mannose side chain

3.

How can you make the lysosome-targeted protein in Qs. 2 get secreted out of the cells?

A.

By adding Tunicamycin to the medium

B.

By adding Nojirimycin to the medium

C.

By addition Endoglycosidase F to the medium

D.

By adding Endoglycosidase H to the medium

4.

How does the reagent, which makes proteins get secreted in Qs 3 work?

A.

By cleaving all sugars from the glycoprotein

B.

By blocking early pruning of the core carbohydrate side chain

C.

By cleaving O-linked sugars from the glycoprotein

D.

By blocking transfer of GlcNAc to dolichol phosphate

Answer 1

Ans-1- tunicamysin is inhibitor of glycosylation that block the first step of glycosylation. Option C is correct.

Ans-2- all the protein targeted to lysosome has mannose-6-phosphate.

So option C is correct.

Ans-3- glycosylation attaches mannose residue on proteins which phosphorylated to make mannose-6-phosphate, the signal for lysosomal protein. So if we block glycosylation the protein will not enter in lysosome.

Option A is correct.

Ans-4- option D is correct