Tricarboxylic acid cycle (Kreb’s Cycle)

AIM : Oxidation of Acetyl CoA to CO2 and H20. Also connectiong almost all individual metabolic pathways.

LOCATION:Mitochondrial matrix

 

FUNCTION: Generates high amount of NADH/FADH2 that act as fuel for ATP synthesis in ETC.

 

REQUIREMENT: Aerobic conditions only (NADH and FADH2 can be regenerated in ETC only in presence of oxygen)

REACTIONS IN KREB’S CYCLE

(Citrate is Kreb’sStarting Substrate ForMaking Oxaloacetate) –read more

Enzymes Mnemonics

So — citrateSynthetase                   

At —Aconitase

Another —Aconitase

Dance —isocitrate Dehydrogenase

Devon — alpha-ketoglutarate Dehydrogenase

Sipped — Succinyl-CoASynthetase

Down — Succinate Dehydrogenase

Five —fumarase

Drinks — malate dehydrogenase

Regulation of TCA:

Sr. No.

Regulating Enzyme

Inhibitred by

Activated by

1.       

Citrate Synthase

ATP

NADH

Acetyl CoA

SuccinylCoa

 

———–

2.       

Isocitrate dehydrogenase

ATP

NADH

ADP

3.       

Alpha-Ketoglutarate

Succinyl CoA

NADH

 

———–

Availability of ADP is also one of the regulating factors.

Krebs cycle is both catabolic and anabolic in nature , hence regarded as amphibolic

Reactions associated are:

  1. Oxaloacetate →Synthesis of Aspartate
  2. Alpha-Ketoglutarate → Synthesis of Glutamate
  3. Succinyl CoA → Synthesis of Porphyrins and Heme
  4. Mitochondrial Citrate →cytoplasm → cleaved to get acetyl CoA → Synthesis of fatty acids , sterols , etc..

 

Ox — Oxaloacetate

Such As — Aspartate

Keto — alpha-Ketoglutatrate

And

Gluta — Glutamate

Succeded —Succinyl CoA

Merrily — Mitochondrial

In

Proper — Porphyrin

Blood shed — Heme

In

Canada — Citrate

 

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