Corrin/B12 Biochemistry: Cobalamin Adenosyltransferase

The video tutorial explores the transformations of vitamin B12, focusing on its role in human metabolism. It highlights two main enzymes, methionine synthase and methylmalonyl COA mutase, that utilize B12. The tutorial delves into the function of cobalamin adenosyl transferase, explaining how it converts B12 into a form used by methylmalonyl COA mutase. The video also discusses B12's unique properties as a super nucleophile, the significance of its ligands, and the electron transfer mechanism involved in its metabolic processes.

Which two enzymes in humans utilize vitamin B12 for basic metabolism?

• Hexokinase and glucokinase

• Pepsin and trypsin

• Lactase and amylase

• Methionine synthase and methylmalonyl CoA mutase

What is the role of cobalamin adenosyl transferase in vitamin B12 metabolism?

• It degrades fatty acids

• It converts B12 into 5'-deoxyadenosylcobalamin

• It synthesizes ATP

• It converts B12 into methionine

What is the oxidation state of cobalt in vitamin B12 when it acts as a super nucleophile?

• +3

• 0

• +2

• +1

What is the alpha ligand in the B12 molecule?

• Dimethyl benzimidazole

• Triphosphate

• Ribose

• Adenosyl group

In the mechanism of B12 as a super nucleophile, what role does ATP play?

• It is a catalyst

• It is the reducing agent

• It acts as a substrate

• It is the oxidizing agent

What is the leaving group in the electron transfer process involving B12 and ATP?

• Phosphate

• Triphosphate

• Adenosine

• Ribose

What is the oxidation state of cobalt after the electron transfer in the synthesis of the 5'-deoxyadenosyl group?

• +2

• +1

• +3

• 0

What is the beta ligand in the B12 molecule used in methylmalonyl CoA mutase?

• Dimethyl benzimidazole

• 5'-deoxyadenosyl group

• Adenosine

• Triphosphate

What is the function of the 5'-deoxyadenosyl group in B12 metabolism?

• It synthesizes ATP

• It chelates cobalt

• It is involved in the degradation of propionyl CoA

• It acts as a cofactor for methionine synthase

Which enzyme is responsible for the synthesis of the 5'-deoxyadenosyl group from ATP?

• Methionine synthase

• Cobalamin adenosyl transferase

• Hexokinase

• Methylmalonyl CoA mutase