Final answer:
The enzyme implicated in alkaptonuria is homogentisic acid oxidase. A helpful mnemonic to remember this is 'Alkap for alkaptonuria, hints at acid oxidase,' relating the disorder's name to the enzyme.
Step-by-step explanation:
In alkaptonuria, the enzyme that is impaired is homogentisic acid oxidase. This enzyme is crucial for the proper metabolism of the amino acids phenylalanine and tyrosine. Without the activity of homogentisic acid oxidase, a buildup of homogentisic acid occurs, leading to the symptoms of alkaptonuria, such as darkened skin, brown urine, joint damage, and other complications.
To remember this, you can use the mnemonic: "Alkap for alkaptonuria, hints at acid oxidase," to relate the disorder's name with the deficient enzyme.