Triglyceride Synthesis Lecture Notes

Introduction

• Triglycerides: Formed by linking fatty acids to a glycerol molecule.
• Essential Components:
  • Fatty Acids: Specifically fatty acyl CoAs (three needed).
  • Glycerol: Serves as the three-carbon backbone.
• Process also known as Lipogenesis.

Fatty Acids Preparation

• Synthesized from Malonyl-CoA as a precursor.
• Involves enzymes such as fatty acid synthase and acyl carrier protein.

Glycerol Source

• Derived from Adipose Tissue during lipolysis.
• Can also come from Glycolysis via conversion of Dihydroxyacetone Phosphate (DHAP) to glycerol.

Conversion of DHAP to Glycerol

• DHAP is converted to Glycerol 3-Phosphate using NADH (reducing to NAD+).
• In liver, Glycerol Kinase adds a phosphate to glycerol forming Glycerol 3-Phosphate.

Triglyceride Synthesis Steps

1. Fatty Acyl CoA Attachment:
   • Step 1: Attach Fatty Acyl CoA #1 to Glycerol 3-Phosphate using acyl transferase, losing CoA, forming Lysophosphatidic Acid.
   • Step 2: Attach Fatty Acyl CoA #2 (must be unsaturated) forming Phosphatidic Acid.
   • Step 3: Remove phosphate group using phosphatidic phosphatase, then attach Fatty Acyl CoA #3 using acyl transferase, creating a triglyceride.

Final Product

• Triglyceride or Triacylglycerol: Contains three fatty acyl groups attached to glycerol.

Utilization of Triglycerides

• Packaged into Very Low-Density Lipoproteins (VLDL).
• VLDL transports triglycerides to adipose tissue.
• Lipoprotein Lipase in the blood releases triglycerides into adipose tissue for storage.

Recap

• Synthesis involves converting glycerol and attaching fatty acids sequentially using specific enzymes.
• Final product transported in VLDLs for storage in adipose tissue.

Next Steps

• Further study will explore the relationship between triglycerides and cholesterol metabolism.