Question

Give the substrate of each of the following enzymes: a. urease b. succinate dehydrogenase c. aspartate transaminase d. tyrosinase

Short answer

a) urea, b) succinate, c) aspartate, d) tyrosine

Step-by-step solution

Identify the substrate for urease

To determine the substrate for urease, remember that urease is an enzyme that specifically catalyzes the hydrolysis of urea. Therefore, the substrate for urease is urea.

Identify the substrate for succinate dehydrogenase

Succinate dehydrogenase is an enzyme that catalyzes the oxidation of succinate to fumarate in the citric acid cycle. Therefore, the substrate for succinate dehydrogenase is succinate.

Identify the substrate for aspartate transaminase

Aspartate transaminase is an enzyme that transfers an amino group from aspartate to alpha-ketoglutarate, producing oxaloacetate and glutamate. Hence, the substrate for aspartate transaminase is aspartate.

Identify the substrate for tyrosinase

Tyrosinase is an enzyme involved in the production of melanin and catalyzes the oxidation of tyrosine to DOPA (dihydroxyphenylalanine). Therefore, the substrate for tyrosinase is tyrosine.

Key concepts

Urease Substrate

Urease is an enzyme that plays a crucial role in the hydrolysis of urea. It specifically catalyzes the breakdown of urea into ammonia and carbon dioxide. This enzyme is commonly found in soil bacteria and some plants, helping to manage nitrogen levels in environments.

Key Points about Urease:

• Hydrolyzes urea.
• Substrate: Urea
• Produces ammonia and carbon dioxide.

Understanding urease's function is essential in fields like agriculture and medical diagnostics, where managing urea levels can be crucial for soil health and patient care respectively.

Succinate Dehydrogenase Substrate

Succinate dehydrogenase is an enzyme that participates in the citric acid cycle (Krebs cycle), an important energy-producing process in cells. It catalyzes the oxidation of succinate to fumarate, alongside the reduction of ubiquinone to ubiquinol in the electron transport chain.

Key Points about Succinate Dehydrogenase:

• Involved in the citric acid cycle.
• Substrate: Succinate
• Converts succinate to fumarate.

This enzyme is essential for energy metabolism in both prokaryotic and eukaryotic cells, making it a pivotal point of study in biochemistry.

Aspartate Transaminase Substrate

Aspartate transaminase (AST), also known as aspartate aminotransferase, is an enzyme that catalyzes the transfer of an amino group from aspartate to alpha-ketoglutarate, forming oxaloacetate and glutamate.

Key Points about Aspartate Transaminase:

• Involves amino acid metabolism.
• Substrate: Aspartate
• Converts aspartate and alpha-ketoglutarate to oxaloacetate and glutamate.

AST levels are often measured in liver function tests, as elevated levels can indicate liver damage or disease.

Tyrosinase Substrate

Tyrosinase is an enzyme vital for melanin production in organisms. It catalyzes the oxidation of the amino acid tyrosine to dihydroxyphenylalanine (DOPA), which further undergoes polymerization to produce melanin pigments.

Key Points about Tyrosinase:

• Involved in melanin synthesis.
• Substrate: Tyrosine
• Converts tyrosine to DOPA.

Understanding tyrosinase is crucial in studies related to skin pigmentation, and disorders like albinism and melasma.