The Localization And Significance Of Arginine And Citrulline In Proteins Of The Hair Follicle

The study investigates the localization of arginine and citrulline in the proteins of rat hair follicles using the Sakaguchi reaction and a modified Ehrlich reagent. It finds that trichohyalin droplets are rich in arginine but lack citrulline, while the hardened inner sheath and medulla show high citrulline and low arginine levels. This suggests a conversion of arginine to citrulline during the transformation of trichohyalin droplets into the fibrous protein of the inner sheath and the amorphous material of the medulla, without protein breakdown. The study supports previous biochemical and electron microscope findings and discusses other potential biochemical roles of the inner sheath and medulla.