Regulation and intracellular localization of the biotin holocarboxylase synthetase of 3T3-L1 cells

Hyo-Ihl Chang, Nadine D. Cohen

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25 Citations (Scopus)


A quantitative assay has been developed to measure holocarboxylase synthetase activity in cellular extracts. This assay was based on measuring the incorporation of [3H]biotin of high specific activity (4.3 Ci/mmol) into purified rat liver apopyruvate carboxylase. With this assay, holocarboxylase synthetase in 3T3-L1 mouse fibroblasts has been monitored. During the differentiation of this cell from a fibroblast to an adipocyte, holocarboxylase synthetase activity was found to increase threefold, while pyruvate carboxylase activity rose 20-fold. The results suggest a possible relationship between the activity of the holocarboxylase synthetase and the level of the biotin-dependent carboxylases within the mammalian cell. Utilizing digitonin fractionation, the intracellular distribution of this enzyme has also been examined. In the 3T3-L1 cell, the large majority (approximately 70%) of the total holocarboxylase synthetase activity was found in the cytosolic compartment.

Original languageEnglish
Pages (from-to)237-247
Number of pages11
JournalArchives of Biochemistry and Biophysics
Issue number1
Publication statusPublished - 1983 Aug 1
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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