Library
Our Biochemistry > Library > Quick Revision Series > Regulatory Mechanisms- Lipid Metabolism (Summary Chart)
Regulatory Mechanisms- Lipid Metabolism (Summary Chart)
- February 23, 2020
- Posted by: Namrata Chhabra
- Category: Quick Revision Series
No Comments
Enzyme | Pathway | Effect of substrate concentration | Allosteric Modification/Feedback Inhibition | Induction/ Repression | Clinical Significance |
Acetyl CoA  Carboxylase | Fatty acid synthesis | Activity increases during well-fed state
Activity decreases during fasting |
Activator-
Citrate, ATP Acetyl CoA Insulin-by causing de-phosphorylation by stimulating protein phosphatase Inhibitors- Long-chain fatty acids, Epinephrine, Glucagon- via changes in phosphorylation state through c AMP mediated phosphorylation cascade |
Induced by Insulin
Repressed by Glucagon |
Activity decreases in diabetes Mellitus |
Carnitine Acyl Transferase | Carnitine shuttle | Activity is low in the fed state and high during fasting | Activated by Glucagon through lipolysis and provision of fatty acids for oxidation
Inhibited by insulin and malonyl CoA |
Inherited CAT-I deficiency affects only the liver, resulting in reduced fatty acid oxidation and ketogenesis, with hypoglycemia. | |
HMG CoA Reductase | Cholesterol synthesis | Activity is low in the fasting state, | Activated by Insulin, Thyroid hormone
Inhibited by –Glucagon, Glucocorticoids (by reversible phosphorylation) Dietary cholesterol (Hepatic synthesis) Mevalonate and cholesterol,the products of the pathway
|
Expression of HMG CoA reductase is regulated by sterol regulatory element binding protein
Also induced by Insulin |
Activity high in Diabetes mellitus due to availability of excess Acetyl CoA.
Activity is inhibited by statins used as cholesterol-lowering drugs. |
Author:Namrata Chhabra

With over 38 years of experience as a Medical Educator, Medical Biochemist, and Researcher, Dr. Namrata Chhabra has a proven track record of leading and contributing to clinical, academic, and research initiatives that advance medical science and education. She holds an M.B.B.S., an M.D. and Ph.D. in Medical Biochemistry, and a Master's in Health Professions Education (MHPE). She is also a FAIMER Fellow, a prestigious recognition of her excellence in medical education and research.
Currently, she serves as the Associate Dean of Admissions, Chair of the Admissions Committee, and a Professor of Biochemistry at the American University of Antigua College of Medicine (AUACOM). In this role, she oversees the academic quality, curriculum development, faculty development, accreditation processes of the college, and student recruitment. She also teaches and mentors medical students, conducts and supervises biomedical and educational research projects, and publishes and presents her findings in national and international journals and conferences. Additionally, she is the author of three comprehensive textbooks on Medical Biochemistry, which are widely used by medical students and professionals. She is passionate about improving the health outcomes of communities and individuals by fostering a culture of innovation, collaboration, and excellence in medical education and research.
Leave a Reply Cancel reply
You must be logged in to post a comment.