Chapter 1 29 therefore possess a considerable dipole moment. If, according to the Steinert-inspired model of the IF structure, the coiled-coil dimers are associated in an anti-parallel fashion, there will be no net dipole. On the other hand this is contrary to the findings of Algie72 in which he found intact mammalian keratin fibers were dipolar in nature. This was confirmed in experiments by Emory Menefee.73 By using a sensitive electrometer he found a current flowed between the parallel transversely cut faces of porcupine quill hard keratin as the temperature was raised to the point of disorganizing the structure of the proteins. Such a current could only have flowed if a high proportion of the α-helical proteins in the initial sample had been cooperatively aligned in the same direction. Menefee also showed that 38% of the dry quill volume consisted of these unidirectionally oriented helical proteins. This is consistent with the proportion of the intermediate filaments (microfibrils) of the keratin composite seen in sections of porcupine quill tip under the transmission electron microscope.34 Such a thermal depolarization current would not have occurred if the coiled-coil dimers of the IFs had been present in the anti-parallel arrangement of the Steinert model. Sadly, Menefee’s experiments have not yet been repeated using human hair. On the other hand there is no reason to suspect results would be any different. The overwhelming argument is thus that the α-helical protein chains in the IFs of the human hair keratin composite all face in the same direction (and incidentally with the amino ends of the protein chains pointing towards the hair tip). In arguing the case against the anti-parallel model Feughelman et al.69 point out the Steinert-inspired cross-linking work involved the in vitro assembly of the KIFs from isolated type-I and type-II proteins and that this does not necessarily mimic the conditions for IF assembly in the hair follicle. Models for the organization of the proteins in the KIFs of the human hair keratin composite based upon an all-parallel alignment of the constituent coiled-coil dimers have been presented by Feughelman et al.70 and it was said “this structure completely correlates with all physical swelling data, all electron microscope