For the determination of the kinetic mechanism with GSSG as the substrate, concentrations up to 60 [micro]M of the disulfide were used in order to avoid the strong substrate inhibition
observed at moderate or high concentrations of GSSG.
This is due to some advantages presented by SSF, as follows (Singhania et al., 2010): the enzymes are produced by microorganisms directly on substrates insoluble in water that makes easier their recovery; the enzymes produced in SSF are less susceptible to substrate inhibition
problems and present higher stability to temperature and pH variations.
GraphPadPrism 5 software was used to calculate regressions, including allosteric kinetics ([V.sub.0]= Vmax*[S]h/(K+ [S]h), where h is the Hill slope, MichaelisMenten ([V.sub.0] = Vmax*[S]/(Km + [S]) and MM with substrate inhibition
([V.sub.0]=Vmax*[S]/(Km + [S]*(1 + [S]/Ki).
fervidus enzymes show substrate inhibition
at very low sulfopyruvate concentrations (100 [micro]M, i.e., 2.5-fold or 1.4-fold the sulfopyruvate [K.sub.M] values of these enzymes, resp.) .
The kinetic models Michaelis-Menten equation and substrate inhibition
equation were fitted to the data of metabolic rates versus substrate concentrations and displayed in (1) and (2), respectively.
The natural of cephalosporin C acylase catalyzed the CPC to 7-ACA directly in a very low efficiency (14,15,16), significant substrate inhibition
(14), and product inhibition (14).
The two binding sites have been used to explain the activation and substrate inhibition
and biphasic saturation curves for the cytochrome P450 enzymes .
They used some kinetic models including substrate inhibition
to determine the biokinetic parameters; the results were [[mu].sub.max] = 0.21 [h.sup.-1] and [q.sub.max] = 144 mmol/[g.sub.cell]/h with CO inhibitory effects on cell growth ([P.sup.L.sub.CO] > 60 kPa) and gas uptake ([P.sup.L.sub.CO] > 80 kPa).
arises as a secondary effect," Biochemistry, vol.
This is consistent with work that demonstrated substrate inhibition
via an allosteric binding site (Zhang et al.
[Ks.sub.[beta]] = [k.sub.-5]/[k.sub.5]: substrate inhibition
[6, 7], in which case [[alpha].sub.1] = [V.sub.max], [[beta].sub.0] = [K.sub.m] and [[beta].sub.1] = 1, if p =1 and q = 2 (2) corresponds to a substrate inhibition
model  and if p = q = 2 (2) can be interpreted in terms of an allosteric mechanism [4, 9].