Inhibition restrictions

Nevertheless, for the production of the flavour-active aromatic alcohol derivatives, such as the corresponding aldehydes and acids, metabolic engineering approaches have to compete with conventional oxidative biocatalysis starting from the natural alcohol as a substrate. For instance, the whole-cell oxidation system based on Pichia pastor is AOX already described in Sect. 23.4.1.2 can also be used to convert benzyl alcohol to benzaldehyde in aqueous media although product inhibition restricted the final product concentration to about 5 g L h indicating the need for aqueous-organic two-phase reaction media [51]. Phenylacetalde-... 

Factors that influence the duration of the log phase are inoculum concentration, cell growth rate, nutrient availability, and accumulation of inhibitory metabolites. For adherent cells, the end of the log phase may also occur at confluence, when cells cover all the available growth surface, at which point contact inhibition restricts further growth. 

R. J. Rodriguez (1993). Polyphosphate present in DNA preparation from filamentous fungal species of Colleotrichum inhibits restriction endonucleases and other enzymes. Anal. Biochem., 209, 291— 297. 

The remarkable specificity of A-[Rh(DPB)2phi] + enables the efficient inhibition of the restriction endonuclease Xbal. Notably, no comparable inhibition of Xbal is achieved with other metallointercalators and A-[Rh(DPB)2phi] + also does not inhibit restriction enzymes that bind to alternative sequences. Thus, this coordination complex effectively mimics a DNA-binding protein. 

Nebularine. Nebularine(44) is a naturaHy occurring purine riboside isolated from S.jokosukanensis (1,3,4). It is phosphorylated, and inhibits purine biosynthesis and RNA synthesis, but is not incorporated into RNA by E. coli RNA polymerase. It has also found appHcation as a transition state analogue for treatment of schistosomiasis and as a substrate for the restriction endonuclease, Hindll (138—141). 

BVdU differs from IdU and F TdU by being specifically phosphorylated in the 5 -position by herpes simplex vims type-1 (HSV-1) induced thymidine kinase. This restricts its action to cells infected by HSV-1. It is less active against genital herpes (HSV-2). HSV-l-induced thymidine kinase converts BVdU to the corresponding 5 -mono- and diphosphate, but HSV-2-induced thymidine kinase stops at the stage of the 5 -phosphate of BVdU. Apparendy, cellular kinases phosphorylate BVdU-5 -diphosphate to the corresponding 5 -triphosphate, which inhibits HSV-1 DNA polymerase to a greater extent than similar cellular DNA polymerases. 

Inhibitors are materials that reduce either one or both of the partial corrosion reactions as in Fig. 2-5. Anodic or cathodic inhibitors inhibit the anodic or cathodic reaction respectively so that the rest potential becomes either more positive or more negative. Most inhibitors, however, inhibit the anodic partial reaction. This is because the transfer of metal ions can be more easily restricted than that of electrons. 

Branching can to some extent reduce the ability to crystallise. The frequent, but irregular, presence of side groups will interfere with the ability to pack. Branched polyethylenes, such as are made by high-pressure processes, are less crystalline and of lower density than less branched structures prepared using metal oxide catalysts. In extreme cases crystallisation could be almost completely inhibited. (Crystallisation in high-pressure polyethylenes is restricted more by the frequent short branches rather than by the occasional long branch.)... 

Radiolytic oxidation is important to the design and operation of reactors because it adversely affects key graphite properties and, by removing moderator material, may bring about the need for increased fuel enrichment. As mentioned earlier, an inhibitor (methane) is added to the coolant to reduce radiolytic oxidation to acceptable levels. However, access of the inhibitor to the inner portions of the moderator brick must be assured. Two approaches have been adopted in the AGRs to provide this access. Vertical methane access holes are provided in the fuel bricks and in the later stations, Heysham II and Tomess, a pressure drop from outside to inside the brick was established to cause an enhanced flow through the brick. The amount of inhibitor added must be restricted, however, because the carbon inhibition reaction product deposits on the fuel pin and restricts heat transfer to the coolant, thus reducing reactor efficiency. 

Condttlonlng evont - CondKlons or restrictions that apply to any logic gate (for priority and Inhibit gates). 

Locomotive diesels As larger volumes of coolant are required in railway locomotives than in road vehicles, the cost of inhibition is proportionally greater. An additional factor is the possibility of cavitation attack of cylinder liners. These considerations place a restriction on the choice of inhibitors. In the past, chromates have been used at concentrations of up to 0-4%, but their use presents handling and disposal problems. Chromates cannot be used with ethanediol antifreeze solutions. A IS I borate-metasilicate at a concentration of 1 % has been used in the UK. Nitrate is added to this to improve inhibition of aluminium alloy corrosion. Tannins and soluble oils are also used, but probably to a lesser extent than in the past. The benzoate-nitrite formulation (formerly BS 3151) is effective and has been used by continental railways . ... 

In the presence of suffident metal ions such as zinc, phosphate defidency is known to inhibit growth and increase yields of dtric add. However, phosphate is added not only as a source of phosphorus but also as phosphoric add to addify the medium. Restricted growth but good citric add yield is also achieved by maintaining iron and zinc defidency hence low phosphate levels are not necessary. 

Studies on the mode of action of the penicillins in inhibiting bacterial cell-wall biosynthesis suggest that the members of this class of antibiotics (including the closely related cephalosporins) are conformationally restricted substrate analogs... 

Gripon P, Cannie I, Urban S (2005). EfScient inhibition of hepatitis B virus infection by acylated peptides derived from the large viral surface protein. J Virol 79 1613-1622 Harris RS, Liddament MT (2004) Retroviral restriction by APOBEC proteins. Nat Rev Immunol 4 868-877... 

Against high levels of computer control Is the pre-batch preparation time required for sequencing, software writing and parameter setting, the full details of the latter of course often not available. This activity Is acceptable as a precursor to full scale production but Is felt restrictive and could Inhibit flexibility In a pilot plant. 

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