ROS & Oxidative Stress

Question 1

Proteins most sensitive to ROS damage

Answer 1

proline, histidine, argenine, cysteine

Question 2

How do ROS cause damage

Answer 2

dirupts secondary and tertiary structure, breaks peptide bonds like cross linking of collagen, premature protein degradation

Question 3

DNA damage

Answer 3

OH radical damage to purine and pyrimidine bases

= DNA breakage or point mutations

unrepaired - dysfunctional proteins = cancer

Question 4

PUFA damage

Answer 4

peroxidation of:
1. LDLs
2. membrane phospholipids (cell, mito, ER, nucleus disruption of membranes like RBC hemolysis)
3. peroxidation releases reactive aldehydes react with proteins, DNA, spreads damage

Question 5

Clinical conditions involving oxidative stress

Answer 5

1. inflammation (arthritis, Alzheimer’s, MS, infection, imjury)
2. atherosclerosis
3. ischemia/reperfusion injury (lack of O2 then sudden reintroduction of O2 to tissue damages/oxidizes)
4. aging