University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

110

Pages:

6
Author:

Sheha A.

Provision of NADPH for Fatty Acid Synthesis: NADPH Significance: NADPH is essential for fatty acid synthesis as it provides the reducing power required for the process. NADPH Sources: The image mentions two primary sources of NADPH: HMP Shunt Pathway: The pentose phosphate pathway (HMP shunt) is a major source of NADPH. Malic Enzyme Reaction: This reaction, occurring in the cytosol, also generates NADPH. Role of Enzymes: Malic Enzyme: This enzyme catalyzes the oxidative decarboxylation of malate to pyruvate, generating NADPH in the process. Isocitrate Dehydrogenase: This enzyme is involved in the citric acid cycle and also contributes to NADPH production. Fatty Acid Biosynthesis De Novo Synthesis: This is the process of synthesizing fatty acids from scratch, using acetyl-CoA as a building block. Key Enzyme: Fatty acid synthase is the key enzyme involved in this process. Products: The primary product of de novo synthesis is palmitic acid (16 carbons). Chain Elongation: Two Systems: There are two systems for the synthesis of long-chain fatty acids: Microsomal Elongation System: This system elongates fatty acids by adding two carbons at a time. Mitochondrial Elongation System: This system also elongates fatty acids, but it is less efficient than the microsomal system. Fatty Acid Elongation 1. Microsomal Elongation System This system is specific for elongating saturated fatty acids. It utilizes NADPH and malonyl-CoA as substrates. It occurs in the endoplasmic reticulum. 2. Mitochondrial Elongation System This system can elongate both saturated and unsaturated fatty acids. It utilizes NADH and malonyl-CoA as substrates. It occurs in the mitochondria.