CONTENTS 



VI 



Mitosis in the basal layer 

 General theories of growth 

 Periodic growth and cyclic activity 

 Control of epidermal growth 



Competition 

 Patterns of hair growth and control 



Zig-zags, curls and crimps 

 Allometric growth 



Molecular and Macromolecular Structure 

 The present status of the chemical structure of the keratins 



End groups 

 Molecular structure 



Methods of partial degradation 



Non- destructive methods 

 X-ray diffraction 

 The low-angle pattern 



The wide-angle pattern 



The elastic properties and the structure of hair 

 Current crystallographic analysis 



Pleated sheet configurations — Silk fibroin . 



Helical configurations — The a-helix . . 

 Coiled coils and a-filaments 



The organization of a-filaments into larger structures 

 The a-j8 transformation in terms of the a-helix 

 The non-crystalline fraction 

 Other methods of determining chain configuration 



Optical rotation and rotary dispersion 



Infra-red spectra and structure 



Deuterium exchange 



The cross-/? pattern 



Other a-proteins 



Some a- and jS-proteins of insect origin 



Feather keratin 



The Keratinization Process 



The hard keratins 



The development of orientation 



The development of stability 



Thiol and disulphide groups during keratinization 



Nucleic acids and synthesis 



Metabolic enzymes 



Glycogen 



Acid mucopolysaccharides and Schiff-reactive substances 



Phosphatases 



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