What Is Substrate-Level Phosphorylation?

Substrate level phosphorylation: During the process of biological oxidation, substances often generate compounds containing high-energy bonds, and these compounds can be directly coupled to the synthesis of ATP or GTP. For substrate level phosphorylation.

Substrate level phosphorylation

Substrate level phosphorylation: Substances in

Substrate level phosphorylation: refers to the substance

Substrate level phosphorylation

for

Unlike: oxidative phosphorylation (electron transfer level phosphorylation)

1. Oxidative phosphorylation coupling In the process of biological oxidation, when the hydrogen removed by the metabolite is oxidized to produce water through the respiratory chain, the energy released is used for ADP phosphorylation to generate ATP. Oxidation is an exothermic reaction, while ADP generates ATP is an energy-absorbing reaction. These two processes occur simultaneously, that is, the process of coupling phosphorylation during oxidation is called oxidative phosphorylation. The ATP generated in this way accounts for about 80% of the total ATP generation and is the main source of energy required to sustain life activities.

2. Where ATP is formed in the electron transport chain

3. Factors affecting oxidative phosphorylation

(1) Regulation of ATP and ADP: The decrease in the ADP / ATP ratio indicates that the cell stores more ATP, so the oxidative phosphorylation rate is slow or even stopped. Conversely, an increase in this ratio indicates that the cell needs ATP, and oxidative phosphorylation accelerates.

(2) Regulating effect of thyroxine: It leads to enhanced oxidative phosphorylation and promotes oxidative catabolism of the substance. As a result, both oxygen consumption and heat production increase. Therefore, patients with hyperthyroidism often experience symptoms such as increased basal metabolic rate (BMR), fear of heat, and sweating.

(3) Inhibitors of oxidative phosphorylation: There are two main types of inhibitors of oxidative phosphorylation: one is inhibitors that inhibit electron transfer (respiratory chain inhibitors); the other is uncoupling that detaches oxidative phosphorylation Agent. The effect of the respiratory chain inhibitor is combined with the electron transporter at a certain location, which hinders its electron transfer.

Oxidative phosphorylation uncoupling agent does not affect the electron transfer of the respiratory chain, but can reduce or stop the phosphorylation reaction of ATP synthesis. The most common uncoupling agent is 2,4-dinitrophenol (DNP).