biologia celular mod2_4 ciclo cori
TRANSCRIPT
Ciclo de Corio
Ciclo del Ácido Láctico
Ciclo de Corio
Ciclo del Ácido Láctico
Gluconeogénesis.Gluconeogénesis.
Síntesis de Glucosa en el cuerpo humano
• GluconeogenesisGluconeogenesis- principalmente hígado y corteza renal• Tejidos que usan predominantemente la glucosaglucosa y que no
tienen la maquinaria enzimático para sintetizarla: – Cerebro
– Músculo esquelético
– Medula del riñón
– Eritrocitos
– Testículos
Pancreas
Glycogen
Glucose
Pyruvate
CO2
Muscle
Insulin
High Blood Glucose
Glycogen
Glucose
Pyruvate
Liver
MuscleMuscleInsulin stimulates glucose uptake and consumption
LiverLiverGlucagon stimulates glucose synthesis and export
Glucagon
Low Blood Glucose
Fuel Amount Energy(MJ)
Number ofdays supply
CarbohydrateCarbohydrate Free Glucose Glycogen
12 g450 g
0.27.65
30 min18h
FatFat Triglyceride 15 kg 550 55
ProteinProtein 12.5 kg 210 21
The Body’s Fuel Stores
Glucolisis Metabolismo de azucares,
glucogeno, glucosa, fructosa
Los intermediarios de la Glucolisis
• G-6-P puede formar ribose para nucleotidos • F-6-P amino azucares-glucolipidos and glucoproteinas • G-3-P/DHAP lipidos • 3PG serine • PEP amino acidos aromaticos, pirimidinas,
transaminasas • Pyr-alanina
Estas rutas metabolicas no son importantes solo en el metabolismo de la glucosa, sino que generan muchos metabolitos intermedios
G-6-P = glucose 6 phosphate, F-6-P = fructose 6 phosphate, G-3-P = glyceraldehyde 3 phosphate, DHAP = dihydryoxacetonephosphate, 3PG = phosphoglyceraldehyde, Pyr = pyruvate
• La glucosa se forma a partir de compuestos glucogénicos que alimentan la gluconeogénesis.
Categorías:Categorías:
• A) de la conversión directa neta a glucosa sin un proceso de reciclaje significativo como los aminoácidos y el propionato.
• B) los productos del metabolismo parcial de la glucosa en ciertos tejidos y que se transportan al hígado y el riñón para la síntesis de glucosa.
Ciclo de CoriCiclo de Cori
• Forma glucosa a partir del ácido láctico.
• Los eritrocitos que no contienen mitocondrias producen de su glucólisis ácido láctico.
• La glucólisis del músculo por vía anaerobia también produce lactato.
Ciclo de Cori
• Cori, Gerty Theresa de soltera Radnitz; 1896-
1957) Bioquímica checoslovaca nacionalizada estadounidense.
• Estudió en la Universidad Alemana de Praga, donde conoció a Carl Ferdinand Cori, con quien contrajo matrimonio en 1920.
• En 1922 ambos cónyuges emigraron a Estados Unidos y en 1947 compartieron el premio Nobel de Medicina y Fisiología con Bernardo Alberto Houssay por sus trabajos de investigación sobre el metabolismo de los hidratos de carbono y la influencia hormonal en la interconversión de azúcares y almidones en el organismo (ciclo de Cori).
Gerti and Carl Cori
Gerti and Carl Cori won the 1947 Nobel Prize in physiology or medicine for their discovery of the course of the catalytic conversion of
glycogen. In layman's terms, they isolated the enzyme that starts the conversion of animal
starch to sugar. The Coris joined the University faculty in 1931. Gerti was the first American woman to win the Nobel Prize. The Coris weren't the only successful researchers
in their lab; in the ensuing years, six future Nobel laureates worked in the Cori lab early
in their careers.
From Washington University in Saint Louis
Glucolisis Anaerobica
Cuando el proceso respiratorio no puedellevar suficiente oxigeno al tejido para que laglucosa se oxide por completo.
COO- COO-| |C=O + NADH + H+ ===== HO - C - H + NAD+| |CH3 CH3
Piruvato L-Lactato
Metabolic regulation during anaerobic exercise
1. Brain – signal – acetylcholine released at muscle –muscle contraction
2. ATP utilised – stores of ATP (1 s) – phosphocreatine (4 s)
3. Rapid breakdown of glycogen – Ca2+ from sarcoplasmic reticulum and increase in Pi (from ATP breakdown) activates phosphorylase
4. Rapid increased flux through glycolysis – allostericregulation of PFK1 (AMP and Pi) and substratecycling
5. Production of lactate and H+ leading to decreasein pH and increased fatigue
6. Dietary supplements – creatine (5 g/day) and sodium bicarbonate which buffers H+ and delays fatigue
Metabolic regulation during anaerobic exercise (2)
PiruvatoPiruvato LactatoLactato
NADH-H NAD+
Fermentación homolácticaFermentación homoláctica
Posibles rutas para el piruvato
•Etanol (fermentacion)
•Acetyl coA (mamiferos)
•Krebs cycle
•Oxaloacetato - gluconeogenesis
•Lactato (mamiferos)
•Producto final de glucolisis anaerobica
•Gluconeogenesis en higado via el ciclo de Cori
Lactic acid (exercise / Cori cycle)
Substrates
Fructose (from sucrose)
Glycerol and propionate (from odd chain fatty acid -oxidation) are the only components of triglycerides that can be used for glucose production.
Alanine Alanine
Amino acids
2-Oxo acids
Glutamate
Urea
Some amino acids and especially alanine and glutamine (alanine cycle and glutamine cycle used to transfer amino groups from muscle to liver for urea synthesis).
2-Oxoglutarate
PiruvatoPiruvato LactatoLactato
AminácidosAlanina
AminácidosAlanina
GlucosaGlucosa
Ciclo de KrebsCiclo de Krebs
Ciclo de CoriCiclo de Cori
Fosforilación oxidativaFosforilación oxidativa
MúsculoMúsculoSangreSangreHígadoHígadoHígadoHígado
GlucosaGlucosaGlucosaGlucosa
PiruvatoPiruvato
LactatoLactatoLactatoLactato
Glu
cosa
-6-F
os f
at o
Glu
cos a
- 6-F
os f
ato
Glu
c os a
-6-F
os f
at o
Glu
cos a
- 6-F
os f
ato
GlucógenoGlucógenoGlucógenoGlucógeno
LACTATOLACTATO
PiruvatoPiruvato
LactatoLactatoLactatoLactato
Glu
cosa
-6-Fo
sfato
Glu
cosa
-6-Fo
sfato
Glu
cosa
-6-Fo
sfato
Glu
cosa
-6-Fo
sfato
GlucógenoGlucógenoGlucógenoGlucógeno
GLUCOSAGLUCOSAGLUCOSAGLUCOSA
PiruvatoPiruvato
PiruvatoPiruvato LactatoLactato
AminácidosAlanina
AminácidosAlanina
GlucosaGlucosa
Ciclo de KrebsCiclo de Krebs
Ciclo de CoriCiclo de Cori
Fosforilación oxidativaFosforilación oxidativa
Cori Cycle
After intense activity, heavy breathingcontinues.
O2 is used for oxidative phosphorylation in liver.
ATP generated is used for gluconeogenesis from lactate, which arrives in blood from muscle.
Glucose formed in liver returns to muscle toreplenish glycogen stores.
Cori Cycle
Enzyme classes
• Oxidoreductases
• Transferases
• Hydrolases
• Lyases
• Isomerases
• Ligases
1. Oxidoreductases• Enzymes that catalyze oxidoreduction reactions• The substrate that is oxidized is regarded as the hydrogen
donor• Systematic name:
– donor:acceptor oxidoreductase
• Example:
CH3-CH2-OH
NAD+ NADH + H+
CH3-CHO
acceptor
donor
2. Transferases
• Enzymes that transfer a moiety from one compound (donor) to another compound (acceptor)– X-Y + Z = X + Z-Y
• In many cases the donor is a coenzyme
• Systematic name:– donor:acceptor grouptransferase
• Recommended name:– donor grouptransferase or acceptor group transferase
• Example: serine hydroxymethyltransferase
3. Hydrolases• EC number 3.x.x.x
• Enzymes that catalyze the hydrolytic cleavage of C-O, C-N, C-C and a few other bonds.
• Hydrolases can be viewed as transferases (the transfer of a specific group to water as the acceptor)
• Recommended name:– substrate hydrolase
Example: thiolester hydrolase
4. Lyases
• Lyases are enzymes cleaving C-C, C-O, C-N and other bonds by elimination, leaving double bonds or rings, or conversely adding groups to double bonds
• Systematic name:– Substrate group-lyase
• Recommended names:– decarboxylase (elimination of CO2)– dehydratase (elimination of water)
• If the reverse reaction is more important– synthase (do not use synthetase, reserved for Class 6)Example: tryptophan synthase
5. Isomerases
• Enzymes that catalyze geometric or structural changes within a molecule.
• The molecular weight of the substrate does not change.
• Examples:– Epimerases (e.g. ribulose-phosphate-4- epimerase)– Isomerases (e.g. ribose isomerase)