Lipoamidase activity in human serum is due to biotinidase

Cheryl L. Garganta, Barry Wolf*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Lipoamidase, as determined by lipoyl-p-aminobenzoic acid (L-pABA) hydrolyzing activity, and biotinidase in human serum have similar pH profiles, molecular weights, thermostabilities, and are similarly inhibited by p-hydroxymercuribenzoate and not inhibited by phenylmethylsulfonylfluoride. A monospecific polyclonal antibody prepared against biotinidase immunoprecipitated > 95% of serum L-pABA hydrolyzing activity and an identical proportion of biotinidase activity. In addition, children with profound biotinidase deficiency (< 10% normal serum activity) have greatly reduced levels of L-pABA hydrolyzing activity in serum (< 15% of mean normal activity) and obligate heterozygotes have activities intermediate between that of normal and profoundly deficient individuals. These results indicate that most, if not all, of the L-pABA hydrolyzing activity in human serum is due to biotinidase. Moreover, since the Km of L-pABA hydrolysis by serum is high, it is unlikely that lipoic acid is recycled in the serum by biotinidase.

Original languageEnglish (US)
Pages (from-to)313-325
Number of pages13
JournalClinica Chimica Acta
Issue number3
StatePublished - Aug 31 1990


  • Biotinidase
  • Biotinidase deficiency
  • Lipoamidase
  • Vitamin recycling

ASJC Scopus subject areas

  • Biochemistry, medical
  • Biochemistry
  • Clinical Biochemistry


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