homogentisic acid
Học thuậtThân thiện
Definition
Noun: 1. A biochemical compound: Homogentisic acid is a specific organic acid. It is formed inside the body as a temporary, intermediate substance during the metabolic breakdown (catabolism) of the amino acids tyrosine and phenylalanine. Its accumulation is associated with a rare genetic disorder.
Usage
- Homogentisic acid is primarily discussed in biochemical and medical contexts.
- It is the compound that builds up in the blood and tissues of individuals with alkaptonuria, a metabolic disease.
- In a healthy metabolism, homogentisic acid is quickly broken down further and does not accumulate.
Examples
- Scientific Context:
- The enzyme deficiency prevents the further metabolism of homogentisic acid.
- Researchers measured the concentration of homogentisic acid in the patient's urine.
- Medical Context:
- A key symptom of alkaptonuria is urine that darkens upon exposure to air due to the presence of homogentisic acid.
- The long-term deposition of homogentisic acid in connective tissues leads to ochronosis.
Advanced Usage
- Biochemical Pathway: Homogentisic acid is a central intermediate in the catabolic pathway for aromatic amino acids. Its conversion to maleylacetoacetate is catalyzed by the enzyme homogentisate 1,2-dioxygenase.
- Diagnostic Marker: The detection of elevated levels of homogentisic acid in urine is a definitive diagnostic test for alkaptonuria.
Variants and Related Words
- Alkaptonuria (n): The inherited metabolic disorder characterized by the inability to metabolize homogentisic acid.
- Ochronosis (n): The bluish-black discoloration of tissues caused by the long-term deposition of homogentisic acid polymer.
- Homogentisate (n): The salt or ester form of homogentisic acid (e.g., homogentisate 1,2-dioxygenase).
Synonyms
- 2,5-dihydroxyphenylacetic acid: This is the systematic chemical name for homogentisic acid.
- Alcapton (archaic): An older term for the substance, from which "alkaptonuria" is derived.
Notes
- There are no phrasal verbs or idioms associated with this highly technical term. Its usage is confined to scientific nomenclature and medical diagnosis.
Noun
- an acid formed as an intermediate product of the metabolism of tyrosine and phenylalanine