PYRUVATE

 

INTRODUCTION:  Pyruvic acid (CH₃COCOOH) is the simplest of the α-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH₃COCOO−, is a key intermediate in several metabolic pathways. In glycolysis, one molecule of glucose breaks down into two molecules of pyruvate, which are then used to provide further energy, in one of two ways.

SOURCES OF PYRUVATE: Pyruvate is converted into acetyl-coenzyme A, which is the main input for a series of reactions known as the citric acid cycle. Pyruvate is also converted to oxaloacetate by an anaplerotic reaction, which replenishes citric acid cycle intermediates. Also, the oxaloacetate is used for gluconeogenesis. If insufficient oxygen is available, the acid is broken down anaerobically, creating lactate in animals and ethanol in plants and microorganisms.

DESTINATION OF PYRUVATE:  Pyruvate from glycolysis is converted by fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation, or to acetaldehyde and then to ethanol in alcoholic fermentation. Pyruvate is a key intersection in the network of metabolic pathways. Pyruvate can be converted into carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine, and to ethanol. Therefore, it unites several key metabolic processes. Pyruvic acid supplies energy to cells through the citric acid cycle (also known as the Krebs or TCA cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate (in mammals) when oxygen is lacking (fermentation). 

RELATED;

1.  lacticacid/lactate  

2.  Citric acid cycle

3.  Biochemistry

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