Matrix metalloproteinase-1 is the major collagenolytic enzyme responsible for collagen damage in UV-irradiated human skin - Brennan, M; Bhatti, H; Nerusu, K C; Bhagavathula, N; Kang, S; Fisher, G J; Varani, J; Voorhees, J J (Photochem Photobiol, 2003)