Carbohydrate Metabolism & Gluconeogenesis Flashcards
Which organs run gluconeogenesis (90%: 10%)?
Hormone Start Signal? Stop?
liver, kidney (when we starve)
Glucagon, Insulin
What are the substrates for gluconeogenesis (LIVER)
fructose, mannose, other sugars can be isomerized to create glucose. We cannot really call this gluconeogenesis tho
LIVER: AA’s –> Alanine (deamination: - NH3–> in form of ammonia, used to prod, urea = excreted as urine.
Lactate = goes to liver from anaerobic cells
Oxaloacetate (intermediate): from AA, chopped by B-oxidation of odd (C) FA - liver mitochondria
Glycerol: from TRI-G,
Recycling the End products of glycolysis into gluconeogenesis; name the two cycles/describe
Cori - Lactate uptake by liver –> secrete glucose to be utilized my many cells.
Alanine - AA from skeletal mm. –> deaminated –> secrete glucose
What are the 4 enzymes that circumvent irreversible, hexokinase , PFK1, and PK
H: Glucose-6-Phosphatase
PFK1: Fructose 1,6-Bisphosphatase
PK: pyruvate & PEP carboxylase
NAME The Intermediates
H: Glucose-6-Phosphatase
PFK1: Fructose 1,6-Bisphosphatase
PK: pyruvate & PEP carboxylase (if not working? PC)
G6P –> Glucose
F16BP –> Fructose-6-Phosphat.
Pyruvate –> oxaloacetate
Oxaloacetate –> Phosphoenolpyruvate
How does lactate become pyruvate? what is the cost? What is needed for alanine to become pyruvate? how much ATP does this process cost?
reversal of lactate dehydrogenase
2 NAD+ –> 2 NADH
Deamination –> ammonia –> urea
4 ATP
What is the equation for gluconeogenesis using lactate?
2 Lactate + 6ATP + 6H20
What is process of generating phosphoenolpryruvate
What vitamin is needed for proper function of pyruvate carboxylase?
*if PC is not working?
pyruvate (w/biotin) enters mitochondria
Pyruvate carboxylase adds CO2 to pyruvate = oxaloacetate
oxalacetate –>to malate by oxidizing NAHD to NAD+.
Nalate crosses membrane, oxidized back to Oxaloacetate.
Oxaloacetate –> to phosphoenolpyruvate by PEP carbox.
Biotin - B7, B3
no gluconeogenesis, no TCA cycle (PC –> oxaloacetate, which needs to be joined with AcCoa –> Citrate
Pyruvate Carboxylase Deficiency: Explain?
Poor Energy Hypoglycemia Lactic acidosis Elevated pyruvate High Alanine Fibroblast produced lipids
Poor Energy - PC coverts pyruvate to oxalacetate for TCA
Hypoglycemia - No gluconeogenesis
Lactic acidosis - TCA stops. Pyruvate to lactacte = Energy
Elevated pyruvate/Alanine - alanine make pyruvate - reverse
Fibroblast produced lipids - pyruvate to acetyl coA to lipid synthesis.
Glucagon hormone is released at ____ blood glucose and _______ gluconeogenesis and ________ glycolysis. Low energy levels (high AMP) does not favor ________
*glucagon regulates gluconeogenesis through the up regulation of enzymes - not same for insulin
low
favors
inhibits
gluconeogenesis
What are some of the effects of alcohol on gluconeogenesis? (3)
Alcohol forces pyruvate to lactate not letting pyruvate go into the gluconeogenesis pathway.
Bad to be hypoglycemic and drink alcohol.
Aldolase B cleaves ________ to _____ and _______
Fructose 1P to DHAP , and Glyceraldehyde
