Substrate-induced Changes in Protease Active Site Conformation Impact on Subsequent Reactions with Substrates

• DOI: 10.1074/jbc.m110.103549
• Publication Date: 2010-05-19T01:34:55Z
• Authors: Rong Pan (荣 潘); Xue-Jing Zhang (晶...; Zi-Jian Zhang (剑 张子); Yuan Zhou (园 周); Wei-Xi Tian (熙 田维); Rong-Qiao He (乔 赫荣)
• Keywords: Conformational change

Enzymatic catalysis of biochemical reactions is essential to all living systems. The "lock and key" "induced fit" models were early contributions our understanding the mechanisms involved in reaction between an enzyme its substrate. However, whether a given substrate-induced conformation rigid or remains flexible has not yet been determined. By measuring activity intrinsic fluorescence nonspecific <i>Eisenia fetida</i> protease-I with different chromogenic substrates, we show that subsequent protease both are used depending on degree conformational change required. Chromozym-Th- chromosym-Ch-induced conformations unable bind chromozym-U. chromosym-U-induced remained could be further induced by chromozym-Th chromozym-Ch. When low concentrations guanidine HCl disturb enzyme, only small changes chromozym-Th-induced detected, contrast native whose markedly increased. This indicates was relatively compared protease. Utilizing lock key mechanism for secondary substrate may have adaptive value it facilitates high efficiency enzymatic reactions.