Carnitine Biosynthesis and Function

This video tutorial covers the biosynthesis of carnitine, an essential metabolite that transports long-chain fatty acids into the mitochondria. The process involves the synthesis of carnitine from lysine and methionine, primarily in the kidneys. The tutorial details the chemical structure of carnitine, the conserved biosynthesis pathway, and the key enzymes involved. It explains the enzymatic reactions, including the roles of cofactors like vitamin C and iron, and concludes with the final steps of carnitine synthesis and its function in fatty acid transport.

What is the primary function of carnitine in the body?

• To store energy

• To synthesize proteins

• To transport long-chain fatty acids into mitochondria

• To break down carbohydrates

Which amino acids are involved in the synthesis of carnitine?

• Glycine and alanine

• Lysine and methionine

• Valine and leucine

• Serine and threonine

Which organ has the highest activity of carnitine biosynthesis?

• Kidney

• Heart

• Liver

• Brain

From which amino acid does the carbon skeleton of carnitine originate?

• Methionine

• Lysine

• Histidine

• Arginine

What is the role of S-adenosylmethionine in carnitine synthesis?

• It stabilizes the structure

• It provides energy

• It donates methyl groups

• It acts as a coenzyme

How is the carnitine biosynthesis pathway described in terms of conservation?

• It is unique to humans

• It is highly conserved across species

• It varies significantly among mammals

• It is only found in plants

Which enzyme adds a hydroxy group to trimethyllysine?

• Trimethyllysine oxidase

• Trimethyllysine hydroxylase

• Trimethyllysine reductase

• Trimethyllysine transferase

What cofactors are required by trimethyllysine hydroxylase?

• Vitamin A and magnesium

• Vitamin C and iron

• Vitamin B12 and zinc

• Vitamin D and calcium

Which enzyme is responsible for converting gamma-butyrobetaine to L-carnitine?

• Gamma-butyrobetaine hydroxylase

• Gamma-butyrobetaine reductase

• Gamma-butyrobetaine transferase

• Gamma-butyrobetaine oxidase

What is the final product of the carnitine biosynthesis pathway?

• Acetyl-CoA

• L-carnitine

• Betaine

• Glycine