4-Hydroxybut-2-Ylmercapturic Acid

**Semantic type:** Organic Chemical

**Definition:** A modified form of acetylcysteine that is a metabolite of crotonaldehyde and may be found in the urine of smokers.

**Synonyms:** - 2-(N-Acetylcysteinyl)Butan-4-Ol - 4-Hydroxybut-2-Yl Mercapturic Acid - HBMA