Gelatin forms when collagen becomes partly or completely uncoiled, as opposed to the regular triple helix structure of fibrillar collagen. In vivo, once collagens are initially cleaved into clasical 3/4 and 1/4 fragments (by collagenases) they rapidly denature at body temperature and are degraded by gelatinases and other nonspecific tissue proteinases (Chung et al. 2004) to a semi-solid colloid gel. MMP2 and MMP9 are the major gelatinases (Collier et al. 1988, Wilhelm et al. 1989) often referred to respectively as Gelatinase A and Gelatinase B (Murphy & Crabbe 1995). However many other MMPs have gelatinase activity, including MMP1 (Murphy et al. 1982, Isaksen & Fagerhol 2001, Chung et al. 2004), MMP3 (Chin et al. 1985, Isaksen & Fagerhol 2001), MMP7 (Isaksen & Fagerhol 2001), MMP8 (Isaksen & Fagerhol 2001) MMP10 (Sanches-Lopez et al. 1993), MMP12 (Chandler et al. 1996), MMP13 (Knäuper et al. 1993, Isaksen & Fagerhol 2001), MMP16 (Shofuda et al. 1997), MMP17 (Wang et al. 1999), MMP18 (Spinucci et al. 1988), MMP19 (Stracke et al. 2000) and MMP22 (Yang & Kurkinen 1998).