Globular Proteins (L2)

Question 1

Properties of globular proteins

Answer 1

• Tightly folded, spherical
• Water soluble
• Dynamic

Question 2

Function of heme

Answer 2

Serves to bind oxygen reversibly in both hemoglobin and myoglobin; also functions as an electron carrier in cytochromes

Question 3

Characteristics of heme

Answer 3

• Hemes bind covalently

- Heme binds O2 through its lone Fe atom (4 pyrrole rings)

Question 4

Heme binding

Answer 4

• Each globin chain binds 1 heme group and each heme binds 1 Fe ion
• Heme binds to globin via negatively-charged propionate groups (P) to Arg and His residies and vinyl (V) and methyl (M) groups

Question 5

Importance of different heme side groups

Answer 5

Several types of heme found in Hb and cytochrome