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)