Reducing vs. Non-reducing Conditions

Question 1

What do reducing conditions do?

Answer 1

disulfide bonds between cysteine residues are broken, disrupting quaternary structure of proteins that consist of more than 1 subunit
- bands visualized under reducing conditions reflect size of individual subunits

Question 2

What do non-reducing conditions do?

Answer 2

if reducing agents not used, disulfide bonds remain intact
- for proteins with more than 1 subunit, band will reflect molecular weight of entire protein