Journal of Molecular Evolution

, Volume 18, Issue 2, pp 121–129

A comparison of lizard claw keratin proteins with those of avian beak and claw

  • J. M. Gillespie
  • R. C. Marshall
  • E. F. Woods


The outer shell of translucent keratin has been dissected from the claws of the lizard,Varanus gouldii. It is free of calcium and hydroxyproline, in contrast to the fibrous support, and contains proteins rich in glycine (28 residues %) and half-cystine (13%). These proteins have been obtained in soluble form by treatment with 2-mercaptoethanol in 8M urea at pH 11 followed by alkylation with iodoacetate to giveS-carboxymethyl kerateines. The three major components resolved by SDS polyacrylamide gel electrophoresis have been isolated by fractional precipitation with ammonium sulfate followed by chromatography on DEAE-cellulose or Sephadex. Two of the components, low in tryptophan content, appear to be homologous and are relatively homogeneous with respect to both size and charge whereas the third, a tryptophan-rich material, appears to contain about 20 different molecular species as judged by gel electrophoresis in urea at pH 8.9. The molecular weights of two of the isolated omponents (the tryptophan-rich and the major of the two tryptophanpoor components) are about 13000 as determined by equilibrium ultracentrifugation studies.

The major lizard claw proteins are therefore similar in size and glycine content to the proteins of avian beak and claw but differ in containing more cystine and less tyrosine. On the other hand, the reptilian proteins resemble the mammalian high-tyrosine proteins (Type II) in cystine content and overall amino acid composition, but differ in size with the lizard proteins being larger. It is suggested however that they are unlikely to be homologous.

Key words

Varanus Lizard Claw Keratin Electrophoresis Protein Fractionation Glycine Tryptophan 


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  1. Baden HP, Maderson PFA (1970) J Exp Zool 174:225–232PubMedGoogle Scholar
  2. Baden H, Sviokla S, Roth I (1974) J Exp Zool 187:287–294PubMedGoogle Scholar
  3. Bonner WM, Laskey RA (1974) Eur J Biochem 46:83–88PubMedGoogle Scholar
  4. Bradbury JH, Chapman GV, King NLR (1966) Proc Third Int Wool Text Res Conf Paris I:359–364Google Scholar
  5. Davis BJ (1964) Ann NY Acad Sci 121:404–427PubMedGoogle Scholar
  6. Eastoe JE (1967) Composition of collagen and allied proteins. In: Ramachandran GN (ed) Treatise on collagen. Vol I. Academic Press Inc, London: pp 1–72Google Scholar
  7. Fraser RDB, MacRea TP, Rogers GE (1972) Keratins, their composition structure and biosynthesis. Charles C. Thomas, Springfield, IllGoogle Scholar
  8. Frenkel MJ, Gillespie JM (1976) Aust J Biol Sci 29:467–479PubMedGoogle Scholar
  9. Gillespie JM (1960) Aust J Biol Sci 13:81–103Google Scholar
  10. Gillespie JM (1972) Comp Biochem Physiol 41B:723–734Google Scholar
  11. Harrap BS, Woods EF (1964) Biochem J 92:8–18PubMedGoogle Scholar
  12. Inglis AS, McMahon DTW, Roxburgh CM, Takayanagi H (1976) Anal Biochem 72:86–94PubMedGoogle Scholar
  13. Laemmli UK (1970) Nature 227:680–685PubMedGoogle Scholar
  14. Marshall RC, Gillespie JM (1976) Aust J Biol Sci 29:1–10PubMedGoogle Scholar
  15. Marshall RC, Gillespie JM (1982) Comp Biochem Physiol (in press)Google Scholar
  16. Marshall RC, Gillespie JM, Inglis AS, Frenkel MJ (1980) Proc 6th Int Wool Text Res Conf Pretoria II:147–158Google Scholar
  17. Roark DE, Yphantis DA (1969) Ann NY Acad Sci 164:245–278PubMedGoogle Scholar
  18. Rudall KM (1947) Biochim Biophys Acta 1:549–562Google Scholar
  19. Sastry LVS, Ramachandran LK (1965) Biochim Biophys Acta 97:281–287PubMedGoogle Scholar
  20. Sengel D, Dhouailly D, Mauger A (1980) Region-specific determination of epidermal differentiation in amniotes. In: Spearman RIC, Riley RA (eds) The skin of vertebrates. Linnean Society Symposium Series No. 9. Academic Press Inc, London, pp 185–197Google Scholar
  21. Walker ID, Bridgen J (1976) Eur J Biochem 67:283–293PubMedGoogle Scholar
  22. Weber K, Osborn M (1969) J Biol Chem 244:4406–4412PubMedGoogle Scholar
  23. Wyld JA (1979) The characteristics of reptilian keratins: an analysis of the molecular events associated with the evolution of the vertebrate epidermis. Thesis, Univ Conn, StorrsGoogle Scholar
  24. Wyld JA, Brush AH (1979) J Mol Evol 12:331–347PubMedGoogle Scholar
  25. Yphantis DA (1964) Biochemistry 3:297–317Google Scholar

Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • J. M. Gillespie
    • 1
  • R. C. Marshall
    • 1
  • E. F. Woods
    • 1
  1. 1.Division of Protein ChemistryCSIROParkvilleAustralia

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