Chapter 7

Question 1

Prosthetic Groups

Answer 1

Groups that are tightly & stably incorporated into a protein’s structure by covalent or noncovalent forces.

Question 2

Co-Factors

Answer 2

Can associate either directly with the enzyme or in the form of a cofactor-substrate complex.

Question 3

Co-Enzymes

Answer 3

Serve as recyclable shuttles that transport many substrates from one point within a cell to another.

Question 4

4 Mechanisms Used to Facilitate Catalysis

Answer 4

• Catalysis by Proximity
• Acid-Base Catalysis
• Catalysis by Strain
• Covalent Catalysis

Question 5

What Amino Acids are involved in Acid-Base Catalysis (HIV Protease)

Answer 5

• Asp X
• Asp Y

Question 6

What Amino Acids are involved in Covalent Catalysis

(Chymotrypsin)

Answer 6

• Asp 102
• His 57
• Ser 195

Question 7

What Amino Acids are involved in Covalent Catalysis

(Frustose-2,6-Bisphosphatase)

Answer 7

• Glu 327
• His 392
• Arg 257
• His 258
• Arg 307
• Arg 352
• Lys 356

Question 8

Isozymes

Answer 8

Distinct enzyme forms that catalyze the same reaction.

Question 9

LDH

Answer 9

Lactate Dehydrogenase

Question 10

Isozymes of LDH

Answer 10

• HHHH (I₁) [Heart Tissue]
• HHHM (I₂)
• HHMM (I₃)
• HMMM (I₄)
• MMMM (I₅) [Liver}

Question 11

CK

Answer 11

Creatine Kinase

Question 12

Isozymes of CK

Answer 12

• CK-MM [Skeletal Muscle]
• CK-BB [Brain]
• CK-MB [Heart & Skeletal Muscle]

Question 13

Troponin

Answer 13

A complex of 3 proteins involved in muscle contractions in skeletal & cardiac muscle but NOT in smooth muscle

Question 14

Biomedical Importance of Troponin

Answer 14

• Immunological measurement of plasma levels of cardiac Troponins I & T provide sensitive & specific indicators of damage to heart muscle.
• Troponin levels rise 2-6 hours after an MI & remain elevated for 4-10 days.

Question 15

Additional Clinical Uses of Enzymes

Answer 15

• Tools for determining the concentration of critical metabolites
• Tools for the treatment of injury & disease
• Tools for diagnosis