ENZYMOLOGY OF PROTEOLYTIC PROCESSES
Enzymatic processes after slaughter:
1. Autolytic process: cathepsins and other enzymes of hide itself are involved.
2. Deterioration process: proteolytic activity of bacterial enzymes.
3. Processes intentionally carried with enzymatic preparations like soaking and unhairing
4. Bating: enzymes attack on proteins remaining in the collagen “wove” after all the beamhouse operations have been done.
Most important enzymes involved in leather making are the proteolytic enzymes.
Proteolytic enzymes: peptidases and proteinases (peptide hydrolases)
Pepsin: active at low pH (formed in stomach mucosa) cleaves gelatin
Renin: almost the same activity
Trypsin: (formed in intestine) most stable at pH ~3.
Chymotripsin: (formed in pancreas) most active at pH 8.
Cathepsin: intercellular enzymes pH 3.7 – 4.
Papain (from papaya): optimum pH 5.5-6 ; but active in temperature 5-66 0C from pH 2.8 to 10.8. Very broad.
Elastase: (formed in pancreas) pH 8.8 optimum activity
Collagenases: bacterial collagenases, animal collagenases; attack collagen in its helical part. pH 8-9
Lipases: (hydrolyze fatty acid esters) attack ester bonds.
