CHEM  30 B  Dr. R. Rinehart 

Chapters 21.3-21.7 & 22.2  
CARBOHYDRATE METABOLISM
 

You are expected to be already familiar with the essentials of carbohydrate chemistry [Ch 17] and catabolism, ATP, oxidative phosphorylation, and the Krebs cycle [Ch 21.1-.2 and 22.1, and 22.3-.6] 

An overview of this whole subject area by James B. Blair at Oklahoma State is at
http://web.archive.org/web/20030223145818/http://opbs.okstate.edu/~Blair/Bioch2344/Chapter11/Chapter11.htm
 http://opbs.okstate.edu/~Blair/Bioch2344/Chapter11/Chapter11.htm
Cellular metabolism and fermentation by Michael J. Farabee at Estrella Mountain CC
http://www.estrellamountain.edu/faculty/farabee/biobk/biobooktoc.html > Cellular metabolism and fermentation
How Cells Make ATP by Charles Mallery at the University of Miami
http://fig.cox.miami.edu/~cmallery/255/255atp/255makeatp.htm
You will [should] love Microbial Metabolism: Energetics by Thomas Terry at the University of Connecticut
http://www.sp.uconn.edu/~terry/229sp03/lectures/catabolism.html

 I.  Digestion: (enzymatic) hydrolysis           

A.  Starch   glucose + maltose + isomaltose;    salivary & pancreatic amylases
           
B.  sucrose   glucose + fructose;   gastric Hcl  and intestinal sucrase
           
C.  maltose glucose;     intestinal maltases
           
D.  lactose   galactose + glucose;     intestinal lactase
                       
lactose intolerance

           
E.  absorption: 3 mechanisms
                       
1.  active transport: glc and gal; uses Na+ and specific carriers

                       
2.  facilitated diffusion: fru and man; carrier proteins
                       
3.  simple diffusion: pentoses & other sugars

 II.  Blood glucose            

A.  hypo- and hyperglycemia
           
B.  fasting blood sugar  60 - 100 mg/100mL [70-110](mg%)
           
C.  renal threshold 180 mg%; > = glucosuria
           
D.  oral glucose tolerance curve (OGTT)
           
E.  hormonal control
                        1. Insulin: promotes glc entry into cells
                                     Insulin-dependent: muscle, adipose, white blood cells, (heart)
                                     Insulin-independent: liver, kidney, brain, erythrocytes, intestine
                        2.  Glucagon:  promotes hepatic glycogenolysis
                       
3. Epinephrine
                        4. Other hormones

The metabolic effects of insulin and glucagon by Lee Crompton at U Manchester 
 http://www.teaching-biomed.man.ac.uk/student_projects/2000/mnby7lc2/METABOLISM.HTM 

            F.  Diabetes mellitus  

Diabetes Mellitus by Todd A. Carlson at Grand Valley State University is really good
http://www2.gvsu.edu/~chm463/diabetes/intropage.html
http://faculty.gvsu.edu/carlsont/diabetes/diabetes/intropage.html
Diabetes mellitus by Lee Crompton at U Manchester
 http://www.teaching-biomed.man.ac.uk/student_projects/2000/mnby7lc2/diabetes.htm
SugarBytes.com from Canada 
http://www.sugarbytes.com/Typehead.htm
  

 III.  Glycolysis: glucose pyruvate

Carbohydrate Metabolism by Michael W. King of Indiana State U School of Medicine
http://web.indstate.edu/thcme/mwking/glycolysis.html 
Carbohydrate metabolism by Patrick M. Woster at Wayne State U
http://wiz2.pharm.wayne.edu/biochem/carbomet.html
Glycolysis [and lots more] by Clarke Earley at Kent State U Stark Campus
http://www.personal.kent.edu/~cearley/PChem/pchem.htm >
> Chemical Reactions and Biochemical Reaction Pathways >
Glycolysis
 
Glycolysis by Paul Reisberg at Wellesley 
http://www.wellesley.edu/Chemistry/chem227/glycolysis/glycolysis.htm
 


            A.  purposes
                        1. ATP production (anaerobic or aerobic)
                        2.  Source of C for biosynthesis

            B.  reactions and enzymes: occurs in cytosol

Glycolysis in 2D [IE OK] and 3D [Chime -- use Netscape]
by Karl J. Miller at George Washington University
http://www.gwu.edu/~mpb/glycolysis.htm 
Glycolysis in Chime by William McClure at Carnegie Mellon U
 http://www.bio.cmu.edu/Courses/BiochemMols/Glycolysis/GlycolysisMain.htm 
Introduction to Glycolysis by Jon Maber at  U Leeds
http://www.terravivida.com/vivida/glyintro/
http://www.beechtreecommon.org/biochemistry/glyintro/
Step by Step Glycolysis
has basic reaction info and animations, by Jon Maber at  U Leeds 
http://www.terravivida.com/vivida/glysteps/
http://www.beechtreecommon.org/biochemistry/glysteps/
also by Jon Maber: Design It Yourself Glycolysis
http://www.terravivida.com/vivida/diygly/
http://www.beechtreecommon.org/biochemistry/diygly/
More info on glycolysis from The University of Texas
http://biotech.icmb.utexas.edu/glycolysis/glycohome.html
Glycolysis by John C. Prez at Texas A&M's Natural Toxins Research Center, Kingsville
http://web.archive.org/web/20021213123243/http://ntri.tamuk.edu/cell/mitochondrion/glycol.html
 http://ntri.tamuk.edu/cell/mitochondrion/glycol.html 


            C.  regulation: by need for energy

                       
1.  phosphofructokinase: inhibited by ATP, citrate; activated by ADP, AMP
                       
2.  pyruvate kinase: inhibited by ATP
                       
3.  hexokinase: inhibited by G-6-P

         D.  fates of pyruvate: the NADH problem

                        1.  anaerobic: reduced to lactate
                               
(or ethanol in yeast, and a variety of other end-products in bacteria)

                        2.  aerobic:  oxidized to Acetyl-CoA [see Ch 22.2]

Animation of the pyruvate dehydrogenase complex 
f
rom Brooks-Cole, publishers of Interactive Biochemistry by Garrett & Grisham 
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/pdc/pdc.html


            E.  net energy yield  [see table]
                        1. anaerobic:  2 ATP/glucose
                        2. aerobic:  36-38 ATP/glucose; role of shuttles 

Diagrams of the malate and glycerol phosphate shuttles by Dr. Keates at the University of Guelph
http://www.chembio.uoguelph.ca/educmat/Chm452/lectur11.htm
Diagrams of the malate and glycerol phosphate shuttles from Dr Mallery's course at U of Miami
http://fig.cox.miami.edu/~cmallery/150/makeatp/gpshuttle.jpg
http://fig.cox.miami.edu/~cmallery/255/255atp/mcb8.10.shuttle.jpg

            F.  Metabolism of other sugars 

Metabolism of non-glucose sugars by Michael W. King of Indiana State U School of Medicine 
http://web.indstate.edu/thcme/mwking/non-glucose-sugar-metabolism.html 

IV. The PENTOSE phosphate PATHWAY
            A.  Purposes
                        1.  generation of NADPH for biosynthesis
                        2.  pentose synthesis
                        3.  alternate catabolic route

            B.  Summary

The pentose phosphate pathway by Karl J. Miller at George Washington University
 http://web.archive.org/web/20080126100102/http://www.gwu.edu/~mpb/pentphos.htm
 http://www.gwu.edu/~mpb/pentphos.htm 

V.  GLUCONEOGENESIS      

A.  main purpose: helps maintain blood glucose level while sparing glycogen
           
B.  reactions and enzymes
                        1.  uses the REVERSIBLE reactions of glycolysis
                        2.  must use several BYPASS REACTIONS

                        
            pyruvate carboxylase
                                    PEP carboxykinase
                                    FDPase
                                    G6Pase

            C.  regulation:
                        1.  PEPCK induced by cortisol
                        2.   FDPase, G6Pase: inhibited by AMP, ADP, accelerated by ATP

            D.  The Cori cycle  

Gluconeogenesis by Michael W. King of Indiana State U School of Medicine
 http://web.indstate.edu/thcme/mwking/gluconeogenesis.html 

  VI.  Glycogen metabolism            

Glycogen metabolism by Michael W. King at Indiana State U School of Medicine
 http://web.indstate.edu/thcme/mwking/glycogen.html 
Glycogen and galactose by Karl J. Miller at George Washington University
http://web.archive.org/web/20080206193709/http://www.gwu.edu/~mpb/polysacc.htm
 http://www.gwu.edu/~mpb/polysacc.htm 

A.  Glycogenesis 
           
B.  Glycogenolysis
           
C.  Hormonal control

The cAMP-dependent protein kinase cascade by Michael W. King of Indiana State U School of Medicine
http://web.indstate.edu/thcme/mwking/ampk.html
 http://web.indstate.edu/thcme/mwking/pkacamp.html 
Inborn errors of carbohydrate metabolism by Michael W. King of Indiana State U School of Medicine http://web.indstate.edu/thcme/mwking/inborn.html#carbo 

Putting it all in perspective
 

See the Metabolic Map of Biochemical Pathways by Boehringer Mannheim GmbH at
 http://us.expasy.org/cgi-bin/show_thumbnails.pl
and then tell me I expect you to know too much!


[for what it's worth] Ronald W. Rinehart, 2002-2007

 

Regulation of glycolysis reactions [interactive] by Clarke Earley at Kent State U Stark Campus

 http://www.stark.kent.edu/~cearley/PChem/Hormones/hormones.htm

Detailed diagram of glycolysis with animations by Robert J. Huskey at U Virginia
http://wsrv.clas.virginia.edu/~rjh9u/glycol.html