Bite-Sized Biochemistry #35 - Fat, Lipid & Cholesterol Movement in the Body
(01/07/11) Lecture by Kevin Ahern of Oregon State University discussing Biochemistry Basics in BB 451. See the full course at oregonstate.edu This course can be taken for credit (wherever you live) via OSU’s ecampus. For details, see ecampus.oregonstate.edu Download Metabolic Melodies at www.davincipress.com Related courses include BB 350 - oregonstate.edu BB 450 - oregonstate.edu BB 100 - oregonstate.edu 1. An enzyme known as thiolase is responsible for putting together two acetyl-CoA molecules to create the acetoacetyl-CoA, which is used to make HMG-CoA. 2. Conversion of lanosterol to cholesterol is a complex, energy intensive process that requires 19 steps and a lot of energy. 3. SREBP (Steroid response element binding protein) is a protein that plays a role in controlling whether or not HMG-CoA reductase is made. When cholesterol is abundant, SREBP is found in the membrane of the endoplasmic reticulum linked to another protein called SCAP through the regulatory (REG) region of SREBP. 4. When cholesterol levels in the cell fall, the SCAP/SREBP complex moves to the Golgi Complex and SCAP binds to a serine protease. The serine protease cleaves SREBP to release the REG region from the region that will ultimately bind to DNA. Highlights Fat/Lipid/Cholesterol Transport 1. Cholesterol in the body is either there as a result of 1) synthesis; 2) diet; or 3) storage/recycling. 2. In the digestive system, bile acids and mechanical agitation of the stomach help emulsify fats. 3 …
