The tryptophan-rich keratin protein fraction of claws of the lizard Varanus gouldii

Abstract

1. 1. Claw keratin of the lizard, Varanus gouldii, is composed mainly of 13,000 m r proteins rich in glycine and cystine. This study deals with a tryptophan-rich group of about 20 constituent proteins comprising about one-third of the mass. 2. 2. As S- carboxymethylkerateines , these proteins were separated by fractional precipitation and gel filtration, then characterized by amino acid analysis, end group analysis, electrophoresis and ultracentrifugation. 3. 3. It is considered that the majority of lizard claw proteins are more closely allied to those of avian beak and claw than feather proteins. 4. 4. Claw keratin also contains minor proteins which resemble mammalian keratin high-tyrosine proteins.