Biologically Active Peptides

Question 1

Function of peptides:

Answer 1

• a biological redox buffer – glutathione
• tissue hormones

- angiotensin, bradykinin

• peptide hormones (hormones whose molecules are
peptides) oxytocin, vasopressin, calcitonin, parathyroid
hormone, gastrin, insulin, glucagon
• endogenous opioid peptides enkephalins and endorphins

Question 2

Carnosine (β-alanyl-L-histidine) – in skeletal muscles

Answer 2

1. has an acid base balance
2. found in the skeletal muscle
3. regulator of myosin-ATPase activity
4. functions as antioxidant
5. chealator of copper

Question 3

glutathione (GSH)

1. what is GSH ?

Answer 3

1. antioxidant capacity
2. protects cells from FREE RADICALS
3. TRI-peptide with GAMMA linkage

Question 4

Define Glutathione as an Antioxidant

Answer 4

• exist in REDUCED GSH and OXIDIZED GSSG states
• increased state of GSSG is indication of OXIDATIVE STRESS
• normal body: reduced state GSH exist
• Low levels of GSH: danger Cardiovascular disease etc

Question 5

In erythrocytes, predominates as the primary scavenger of intracellular hydrogen peroxide (H 2 O 2) ?

Answer 5

Glutathione Peroxidase (Gpx)

Question 6

how to recover GSH from GSSG ?

Answer 6

by GSH being oxidized –using Glutathione Reductase

via NADPH (electron and protons donor)

Question 7

Endogenus opiod peptides

Answer 7

1. B-endorphines
2. Enkephalines
3. Dynorphins

Question 8

Endogenus opiod peptides

Answer 8

1. B-endorphines
2. Enkephalines
3. Dynorphins

Question 9

Enkephalins

Answer 9

• pentapeptides
• have Leu and Met
• powerful pain killer found in all parts of the body
• found in the brain