In Vitro: The reduced activity of methylcrotonyl-CoA carboxylase (MCC) leads to an elevated excretion of 3-methylcrotonic acid, the product of its hydration (3-hydroxyisovaleric acid: 3-HIA), and 3-methylcrotonylglycine, formed by conjugation with glycine.
In Vivo: In male mice (ICR/Jcl) at 8 weeks of age fed the biotin-deficient diet for 6 weeks, the concentration of urinary 3-Hydroxyisovaleric acid is 114.2 mM creatinine, which is higher than the concentration of 35.2 mM creatinine in mice fed the biotin-deficient diet for 4 weeks.