Human skin collagen. Presence of type I and type III at all levels of the dermis.

Human skin was sliced with a dermatome, and the ratio of type I to type III collagens at various depths was assayed by comparing the quantities of peptides of each derived from cyanogen bromide digestion of the cut skin. Although immunofluorescent studies have suggested type III collagen is located predominantly beneath the epidermis and around appendages, biochemical determination demonstrates the same ratio of type I to type III collagen at all levels of the dermis even in the absence of cutaneous appendages.