Autodegradation of 125I-labeled human epidermal cell surface proteins

K. Hashimoto, K. H. Singer, G. S. Lazarus

Research output: Contribution to journalArticlepeer-review


Triton X-100 extracts of cultured human epidermal cells exhibited proteolytic activity as measured by the hydrolysis of [3H]-casein at neutral pH. The majority of endogenous proteolytic activity was inhibited by parahydroxy mercuribenzoate and by mersalyl acid, indicating the enzyme(s) was a thiol class proteinase(s). Crude Triton X-100 extracts were prepared from epidermal cells following labeling of proteins with 125I. Autodegradation of labeled proteins at 37°C was detected as early as 1 hr and reached a plateau level by 4 hr. Degradation was inhibited by thiol class proteinase inhibitors. Among the detergent-solubilized radiolabeled proteins a polypeptide chain of M(r) 155,000 was particularly sensitive to degradation by endogenous thiol proteinase(s).

Original languageEnglish (US)
Pages (from-to)361-364
Number of pages4
JournalJournal of Investigative Dermatology
Issue number6
StatePublished - 1982
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Dermatology
  • Cell Biology


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