User:VincentNoelz

 Lock and key hypothesis 

'This concept was suggested by the 19th-century chemist Emil Fischer''. He proposed that the active modification, just like a key fits into a lock. If one substrate perfectly binds to its active site, the interactions between them will be strongest, resulting in high catalytic efficiency. site and substrate are two table structures that fit perfectly without any further'''

'''As time went by. limitations of this model started to appear. For example, the competitive enzyme inhibitor methylglucoside can bind tightly to the active site of 4-alpha glucanotransferase and perfectly fits into it. However, 4-alpha-glucanotransferase is not active on methylglucoside and no glycosyl transfer occurs. The Lock and Key hypothesis cannot explain this, as it would predict a high efficiency of methylglucoside glycosyl transfer due to its tight binding. Apart from competitive inhibition, this theory cannot explain the mechanism of action non-competitive inhibitors either, as they do not bind to the active site but nevertheless influence catalytic activity.'''

 Induced fit hypothesis 

'Daniel Koshland's'' theory of enzyme-substrate binding is that the active site and the binding portion of the substrate are not exactly complementary. The induced fit model is a development of the lock-and-key model and assumes that an active site is flexible and changes shape until the substrate is completely bound. This model is similar to a person wearing n glove: the glove'''