Question

During gluconeogenesis, what enzymes are critical to overcome the massive energy requirement for generating Phosphoenolpyruvate?

	a.	None of the above
	b.	Pyruvate decarboxylase, PEP carboxykinase,
	c.	Pyruvate decarboxylase, Pyruvate kinase
	d.	Pyruvate carboxylase, PEP carboxykinase
	e.	Pyruvate dehydrogenase, PEP carboxykinase

Fermentation of pyruvate in yeast regenerates oxidizing power under limiting oxygen or anaerobic conditions and requires a specific cofactor. What enzyme is used and what is the cofactor?

	a.	None of the above
	b.	Lactate dehydrogenase, NAD+
	c.	Pyruvate carboxylase, Biotin
	d.	Alcohol dehydrogenase, Zinc
	e.	Pyruvate decarboxylase, TPP

Answer 1

During gluconeogenesis, what enzymes are critical to overcome the massive energy requirement for generating Phosphoenolpyruvate?

Pyruvate carboxylase and PEP carboxykinase.

Pyruvate carboxylase converts pyruvate into oxaloacetate.

PEP carboxykinase converts oxaloacetate into phosphosenol pyruvate (PEP).

Fermentation of pyruvate in yeast regenerates oxidizing power under limiting oxygen or anaerobic conditions and requires a specific cofactor. What enzyme is used and what is the cofactor?

Pyruvate decarboxylase, TPP.

Pyruvate is converted to acetaldehyde by pyruvate decarboxylase with a loss of CO2.

This acetaldehyde is converted to ethanol by alcohol dehydrogenase with the help of NADH.

Pyruvate decarboxylase uses thiamine pyrophosphate (TPP) as a coenzyme.