overview of ROS Physiology and the PPP

Question 1

RBC’s

Answer 1

• use NADPH to help destroy reactive oxygen species (ROS) which are free radicals containing O. ex: superoxide

Question 2

superoxide

Answer 2

picks up an e- and protons to form hydrogen peroxide.
H2O2 broken down to get H2O.
If another e- and H+ gets added, hget hydroxyl free radical which is harmful to DNA

Question 3

GPX and GSH/GSR

Answer 3

destroys peroxides by converting to water. To do, requires 2 molecules of GSH (glutathione).
Has a cysteine, take two and join together to make GSSG, so forming a disulfide bond.
GSR (glutathione reductase) then takes NADPH from PP and uses it to reduce the GSSG to 2 GSH.
This cycle is important because in RBC want to have it to remove ROS that may exist (why there in 1st place, RBC carrying O2 and may accidentally pick up e-) so NEED this cycle there in order to remove.

Question 4

GPx active site

Answer 4

contains selenium which comes from Sec, so need selenium in diet… best source of selenium is brazil nuts