c-terminal propeptide of bka has a protease sensitive structure without any inhibitory effect on bka

in our previous study, we compared the two α-amylase enzymes from bacillus sp.kr8104, bka∆(n44) and bka∆(n44c193) which is the secreted form of it. the results indicated that the presence of 193 amino acids propeptide in the c-terminal of bka∆(n44) changed its enzymatic parameters like an uncompetitive inhibitor in comparison to bka∆(n44c193). in the present study, we cloned the dna sequence of bka∆(n44) which codes the 193 amino acids propeptide in its c-terminal and the effect of this fragment as an inhibitor on bka∆(n44c193) was investigated. we also studied the possible foldase activity of the propeptide in bka∆(n44c193). protease sensitivity of c-terminal 193 amino acid propeptide, bka∆(n44) and bka∆(n44c193) was compared in order to explain why  bka∆(n44c193) is the only secreted form of α-amylase in the culture medium of bacillus sp.kr8104. circular dichroism indicated that the secondary structure of the c-terminal is mostly beta sheeted. at the end we proposed a possible regulatory role for the c-terminal propeptide of bka.