Histidine Catabolism to Oxoglutarate

The video explains histidine catabolism, focusing on the role of histidine ammonia lyase and urocanic acid in UV protection. It details the enzymatic mechanisms involved, including urocanic hydratase and the conversion to formamino glutamate, highlighting histidine's glucogenic properties and its integration into the TCA cycle and gluconeogenesis.

What is the primary enzyme involved in the initial catabolism of histidine?

• Dioxygenase

• Glutamate dehydrogenase

• Histidine ammonia lyase

• Urocanic hydratase

Why is urocanic acid important in the epidermis?

• It provides structural support

• It acts as a moisturizer

• It absorbs ultraviolet light

• It enhances pigmentation

Which enzyme catalyzes the hydration of urocanic acid?

• Glutamate dehydrogenase

• Imidazolone propionase

• Urocanic hydratase

• Histidine ammonia lyase

What is the significance of tautomerization in the conversion of urocanic acid?

• It increases solubility

• It enhances UV absorption

• It allows nucleophilic acyl substitution

• It stabilizes the molecule

What is the final product of histidine catabolism?

• Urocanic acid

• Formimino glutamate

• Glutamate

• Alpha-ketoglutarate

How is histidine classified based on its catabolic pathway?

• Both ketogenic and glucogenic

• Neither ketogenic nor glucogenic

• Glucogenic

• Ketogenic

Which cycle does alpha-ketoglutarate enter after being formed from histidine catabolism?

• Pentose phosphate pathway

• Urea cycle

• Glycolysis

• TCA cycle