Encoding Cathepsin B-like Cysteine Proteinase from Tuberous Root of Sweet Potato. In the process of storage protein utilization it has been shown that many proteinases are involved in the degradation of storage proteins for nutrient mobilization.
Tuberous root is the major storage organ of sweet potato.
Here we report the molecular cloning of a cysteine type proteinase from sprouting zones of tuberous roots. The cloning methods are mainly based on the use of conserved primers and PCR amplification. The full-length cDNA encodes a polypeptide of 352 amino acid residues with calculated Mr of 38.8 kDa. The possible mature N terminal is leucine at amino acid 95 with calculated Mr of 28.2 kDa for the mature enzyme. From these sequence comparison cathepsin B may represent an distinct group of cysteine proteinase which diverge from cathepsin L-like cysteine proteinase early in the evolution.