The present studies have demonstrated that the medulla and inner root sheath cells develop within their cytoplasm a protein that is unique in composition and is present in the trichohyalin granules. The protein is rich in arginine residues, some of which undergo a side-chain conversion in situ into citrulline residues. An unusual Ca2--dependent enzyme activity distinguishable from cross-linking transamidase has been detected in the hair follicle and will act in vitro on trichohyalin protein as the natural substrate. The conversion in vivo must occur during the time that the medullary and inner root sheath cells move up the follicle and their cytoplasm fills with cross-linked protein containing citrulline. The function of citrulline in these proteins is not understood but its formation is a major process during hair growth.

The transfer of arginine from tRNA to the amino terminal region of acceptor proteins has been demonstrated in postribosomal supernatant from guinea-pig hair follicle homogenate. The reaction has no requirement for template nucleic acids, ATP, GTP, or Mg++, and is unaffected by high concentrations of cycloheximide. It is concluded that the arginine transfer activity of the guinea-pig hair follicle is due to the action of a soluble enzyme similar to the arginine transferases previously described for other mammalian tissues.

The ε-(γ-glutamyl)lysine cross-link has been unequivocally localized in the citrulline-containing protein of hair medulla tissue. This was achieved by the isolation of cross-linked peptides that contain citrulline. The peptides were purified by molecular sieving, cation-exchange and paper chromatography and paper electrophoresis and their amino acid compositions are reported. They were detected by analyzing a larger number obtained from a tryptic digest of thermolytic peptides of the medulla protein. There is no evidence at present as to whether the cross-link is in fact interor intrachain, or both.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of the iε-(γ-glutamyl)lysine crosslink in hair proteins. Investigation of transamidases in hair folliclesHarry W. J. Harding and G. E. RogersCite this: Biochemistry 1972, 11, 15, 2858–2863Publication Date (Print):July 18, 1972Publication History Published online1 May 2002Published inissue 18 July 1972https://pubs.acs.org/doi/10.1021/bi00765a019https://doi.org/10.1021/bi00765a019research-articleACS PublicationsRequest reuse permissionsArticle Views97Altmetric-Citations49LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The epsilon-(gamma-glutamyl)lysine cross-link has been unequivocally localized in the citrulline-containing protein of hair medulla tissue. This was achieved by the isolation of cross-linked peptides that contain citrulline. The peptides were purified by molecular sieving, cation-exchange and paper chromatography and paper electrophoresis and their amino acid compositions are reported. They were detected by analyzing a large number obtained from a tryptic digest of thermolytic peptides of the medulla protein. There is no evidence at present as to whether the cross-link is in fact inter- or intrachain, or both.