BIO-310
BIOCHEMISTRY II
IV. WEEK
LECTURE CONTENTS OF 4TH WEEK
• Phosphatidylinositols and sphingosine derivatives may be involved in intracellular signaling.
• Eicosanoids can carry messages.
• Lipids can act as cofactor, hormone or pigment
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https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.nature.com%2Farticles
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https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.mechanobio.info%2Fwhat-is-the-plasma-membrane
%2Fwhy-are-membrane-lipids-asymmetrical%2F&psig=AOvVaw2PB0OdWNARVM-
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https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.researchgate.net%2Ffigure%2FStructure-of-
glycerophosphate-based-lipids-The-lipid-structure-shown-is-1-2_fig2_316998196&psig=AOvVaw2PB0OdWNARVM- q9WN3LggV&ust=1589314685762000&source=images&cd=vfe&ved=0CAIQjRxqGAoTCNCI99zQrOkCFQAAAAAdAAA AABCvAQ
• Sphingolipids have polar head groups and two non-polar tail portions.
• They do not contain glycerol.
• The amino group in the second carbon is bound to a fatty acid by the amide bond. This fatty acid contains 16, 18, 22 and 24 carbon saturated and unsaturated fatty acids.
•In the polar group connected to C-1, - If there is a ceramide,
If phosphokolin is bound, sphingomyelin is located on the plasma membrane of animal cells, and they are involved in surrounding and neurons.
• If glucose is bound; Neutral glycolipids (glucoserebroside)
• If di-, tri-, tetrasaccharide is bound, lactocylseramid (globozit)
• If complex oligosaccharides are attached, the ganglioside is called GM2.
• The most complex sphingolipids are gangliosides.
• They may have sialic acid (N-acetylneuraminic acid).
• Sphingolipids on the cell surface can be used as recognition sites.
• More than sixty sphingolipids were found in human cells.
• The carbohydrate portions of some of them define blood groups and determine the type of blood
suitable for the person in blood transfer.
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• Sphingolipids and phospholipids are broken down in lysosomes.
• Lysosome specific hydrolytic enzymes can do this.
• Type A phospholipases (A1, A2) may form the hydrolysis of one of the two fatty acids.
• Lysophospholipids are formed.
• Each of the Phospholipase C and phospholipase D hydrolyze one of the phosphodiester bonds in the head group.
• Seramide remains left behind sphingophospholipid hydrolyzed in lysozyme. A genetic disorder in any of the enzymes can create a serious health
problem that can lead to accumulation of gangliosides in the cell.
• Eukaryotic cells contain sterols in the structure of the membrane.
• The steroid hormones derived from these serve as signals.
• Some lipids act as cofactors and signal molecules
• Ex. When the phosphatidylinositol bisphosphate is hydrolyzed, the secondary precursor is
diacylglycerol and inositol 1,4,5-triphosphate.
• Prostaglandins derived from arachidonic acid, thromboxanes and leukotrienes are called
eicosanoids.
• There are many molecules derived from them and they have different functions.
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eicosanoid.html&psig=AOvVaw0hk1OG5HtnxCGGuSt2C9tI&ust=1589315448014000&source=images&cd=vfe
&ved=0CAIQjRxqFwoTCNDzks3TrOkCFQAAAAAdAAAAABAD
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%2Fprostacyclins&psig=AOvVaw0hk1OG5HtnxCGGuSt2C9tI&ust=1589315448014000&source=images&cd=vfe&ved=0CA IQjRxqFwoTCNDzks3TrOkCFQAAAAAdAAAAABAd
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.lipidhome.co.uk%2Flipids%2Ffa-eic%2Feicintro
%2Findex.htm&psig=AOvVaw0hk1OG5HtnxCGGuSt2C9tI&ust=1589315448014000&source=images&cd=vfe&
ved=0CAIQjRxqFwoTCNDzks3TrOkCFQAAAAAdAAAAABAi
•While some drugs (NSAIDs) prevent the formation of prostaglandins and thromboxanes, steroid drugs may prevent the formation of leukotrienes.
•D, A, E and K vitamins of fat-soluble vitamins
consisting of isoprene units of these molecules can act as hormones.
•BIOCHEMICAL FORMULAS WILL BE DISCUSSED WITH IN THIS
SECTION
REFERENCES
MAIN : LEHNINGER PRINCIPLES OF BIOCHEMISTRY, DAVID L. NELSON, MICHAEL M.
COX, 5TH EDITION, 2013.
PRİNCİPLES OF BİOCHEMİSTRY, H. R. HORTON, L.
A. MORAN, K. G. SCRİMGEOUR, M. D. PERRY, J.
D. RAWN, PEARSON PRENTİS HALL, 2006.
COLOR ATLAS OF BIOCHEMISTRY, J. KOOLMAN, K. H. ROEHM, GEORG THIEME VERLAG, 2005.
HARPER’S ILLUSTRATED BIOCHEMISTRY, R. K.
MURRAY, D. K. GRANNER, P. A. MAYES, V. W.
RODWELL, LANGE MEDICAL BOOKS/MCGRAW- HİLL MEDICAL PUBLISHING DIVISION, 2003.
BASİC CONCEPTS İN BİOCHEMİSTRY, A STUDENT’S SURVİVAL GUİDE, H. F. GİLBERT, MCGRAW-HİLL HEALTH PROFFESİONS DİVİSİON, 2000.
