Protein metabolism

What is the process of removing the amino group from amino acids called?

Deamination

What cycle is responsible for urea production?

Urea Cycle

What is the role of ubiquitin in protein metabolism?

Ubiquitin tags proteins for degradation.

Which enzyme is responsible for activating ubiquitin?

Ubiquitin activating enzyme

What determines the half-life of a protein?

The N terminus of the protein.

What structure degrades ubiquitinated proteins in eukaryotic cells?

26S proteasome

What is the function of aminotransferases?

They transfer the alpha-amino group to alpha-ketoglutarate.

What does aspartate transaminase catalyze?

The reaction between oxaloacetate and glutamate.

What vitamin is required by transaminases for their function?

Pyridoxal phosphate from Vitamin B6.

What is the role of glutamate dehydrogenase?

It catalyzes the conversion of L-glutamate into alpha-ketoglutarate and ammonia.

How many ATP are required for each urea produced?

4 ATP

What is the first step in the urea cycle?

Bicarbonate is added to ammonia by carbamoyl phosphate synthetase.

What is produced during the hydrolysis step of the urea cycle?

Urea

What is the fate of fumarate in the urea cycle?

It can be hydrated to malate, oxidized to oxaloacetate, or used in gluconeogenesis.

What percentage of nitrogen fixation is done by microorganisms?

60%

What complex is responsible for nitrogen fixation?

Nitrogenase complex

What enzyme converts ammonia into glutamate?

Glutamate dehydrogenase

What is the precursor for other amino acids derived from glutamate?

Glutamine

What defines high-quality protein?

Contains all essential amino acids in required proportions and is easily digestible.