Sigmoidal kinetics, enzymatic

Furthermore, in the system with coupled lipase and lipoxygenase, the production rate of HP is governed by the first enzymatic reaction and mass transfer. When TL,- is small (0 to 1 mM equiv. 3 mM LA), the kinetic curve has a sigmoid shape due to surface active properties of LA and HP [25]. Hydrolysis of TL and the increase of LA favor the transfer of LA. Such a transfer allows the lipoxygenase reaction to progress. Since lipox-ygenation consumes LA and produces HP, catalysis and transfer demonstrates a reciprocal influence. 

The kinetics of the enzymatic dissolution of elastin are very complex and the reaction of elastin fibers with elastolytic enzymes is commonly characterized by a lag phase or a markedly sigmoid time course (cf. Hall and Czerkawski, 1959 Naughton et al., 1960). The length of the slow initial phase is influenced by the enzyme-substrate ratio and the source and method of preparation of the elastin used in the assay the course of the reaction with different enzymes is also influenced by the presence or absence of salts, reducing agents, and many other substances. As a result... 

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