gluconeoglycogen - GLUCONEOGENESIS...

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--  GLUCONEOGENESIS GLUCONEOGENESIS   --   Definition Definition : the  biosynthesis biosynthesis  of glucose   primarily from pyruvate and its precursors. The  liver liver  is the major location for  gluconeogenesis.
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  Why do we produce glucose? Why do we produce glucose?  Need to maintain glucose levels within a  narrow range in blood.  Brain, erythrocytes, and muscles in  exertion use glucose at a rapid rate and  require glucose between meals, especially  after several hours.
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  What is the major precursor? What is the major precursor? The major precursor for glucose biosynthesis  is  pyruvate. pyruvate.
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What are the sources of pyruvate? What are the sources of pyruvate?   lactate lactate –mostly from muscle. Lactate is  produced in great quantities during exertion.  Lactate is released from the muscles to the  blood and travels to the  liver  for conversion  to pyruvate and, ultimately to glucose. 
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  some  amino acid   carbon skeletons- from diet or breakdown of muscle protein during starvation- most important is  alanine alanine   TCA cycle intermediates TCA cycle intermediates Note:  glucose cannot be made from acetyl  CoA
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Gluconeogenesis Gluconeogenesis - beginning - beginning
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           fructose 1,6- bis phosphate                         aldolase                   triose phosphate isomerase dihydroxyacetone              glyceraldehyde   phosphate                         3-phosphate
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                                 GLUCOSE GLUCOSE                      glucose                  P i BYPASS 3  6-phosphatase        ( hexokinase)                       Glucose 6-phosphate    phosphogluco-   isomerase                       Fructose 6-phosphate     BYPASS 2     fructose              P i      ( phospho-    1,6 bisphosphatase                  fructokinase)         Fructose 1,6- bis phosphate
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Bypass number 1. Bypass number 1. Pyruvate to phosphoenolpyruvate Pyruvate to phosphoenolpyruvate This bypasses pyruvate kinase.     Complex scheme .
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a) pyruvate to oxaloacetate Enzyme =  pyruvate carboxylase     Pyruvate has transport system to enter mitochondria Enzyme located inside   mitochondria . Only this enzyme of gluconeogenesis pathway is mitochondrial.
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  Reaction Reaction : :       pyruvate + CO + ATP + H 2   oxaloacetate + ADP + P i  Pyruvate carboxylase requires  biotin  as  cofactor- Carboxylations involving CO 2   almost always use the vitamin  biotin   pyruvate carboxylase- pyruvate carboxylase- acetyl-CoA   absolutely required activator
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gluconeoglycogen - GLUCONEOGENESIS...

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