| Trypsin was biotinylated with NHS-biotin (N-hydroxysuccinimido biotin) and standard cattlehide soaking experiments were conducted in a TRIS buffer solution at pH 7.8 containing 0.02 M of calcium ion. The experiments were performed in an equipment that provided temperature control and mechanical agitation; the flesh and grain sides of the hide were submitted to the soaking, individually. The soaking time was 4 hours at 30(DEGREES)C.;The biotinylated trypsin was detected inside the hide by the biotin-avidin peroxidase technique, and an insoluble dark brown polymer was formed after the oxidation of DAB (3,3'-diaminobenzidine). With the concentrations and experimental conditions used trypsin had limited penetration in the grain and flesh side and increased penetration in highly vascularized area.;In the grain, epidermal-dermal separation was observed. Permeability and enzyme penetration increased by increasing the enzyme concentration, suggesting that better soaking and unhairing is obtained. Pieces treated with trypsin in the grain produced leather with cleaner grain than was shown by the control. |
