Lect14 - 1 Lecture 14 Glycogen Breakdown 2 Important...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Lecture 14 Glycogen Breakdown 2 Important concepts 1. Understand breakdown of glycogen Understand the process (debranching and cleavage) Memorize the products Cofactor of glycogen phosphorylase: pyridoxal phosphate 2. Understand regulation of glycogen breakdown (glycogen phosphorylase) Phosphorylation (phosphorylated a form tends to be active (R); unphosphorylated b form tends to be inactive (T) Allosteric regulation (muscle vs. liver)) Hormone regulation (muscle vs. liver) 3 Glycogen: Glucose Storage Animals glycogen Plants starch Demand of glucose in brain and red blood cells, while other tissues can use fatty acids Glucose taken from glycogen supplies in liver for ready supply (~ 5 mM in blood) But, livers supply is good only for 1/2 day So, noncarbohydrate sources made into glucose Gluconeogenesis Liver cell 5 Glycogen granules 100-400 diameter Contain ~120,000 glucose units 1-2% of muscle weight and Up to 10% of liver weight Contain glycogen synthesis/degradation enzymes Removal of glucoses from nonreducing (many) end, rather than reducing (only one) end Fate of Glycogen Note: Fats cannot ordinarily be made into glycogen a (1>4)-linked D-glucose a (1>6) branches every 8-14 residues Many nonreducing ends, one reducing end 7 What is glycogen? 8 Glycogen Breakdown: 9 Debranching Since glycogen phosphorylase cannot reach all the way to a branch, stops ~4 units away from a branching point a (1>4) transglycosylase moves three glucosyl residues to nonreducing end Then, a-1,6 glucosidase yield glucose (not glucose-1- phosphate) hydrolysis 10 Debranching Glucose is then phosphorylated to Glucose- 6-P i by hexokinase In eukaryotes, transglycosylase and a-1,6 glucosidase in one protein 11 Glycogen Breakdown: 12...
View Full Document

This note was uploaded on 03/04/2012 for the course CHEM 114B taught by Professor Wang during the Spring '09 term at UCSD.

Page1 / 43

Lect14 - 1 Lecture 14 Glycogen Breakdown 2 Important...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online