Patterns Cell-free Extracts

898 k Tange, H. Okita, Y. Nakao, T. Hirata, and T. Suga, Chem. Lett., 1981, 111. 

Takeda, T. Tanahashi, and H. Inouye, Chem. Pharm. Bull., 1981, 29, 970. 

Takaki, and H. Kameoka, Chem. Lett., 1981, 1257. 

Time-course studies with 14COa showed that in a Thymus sp., y-terpinene was converted into p-cymene and thymol in sequence,916 and the appropriate y-terpinene synthetase (MW ca. 96 000) was partially purified. Tracer studies indicated that loss of a proton from C-5 of the a-terpinyl-like precursor to form the A4-un-saturation was accompanied, perhaps concertedly, by a 1,2-hydride shift from C-4 to C-8 to form y-terpinene.917 Neomenthyl-p-D-glucoside was a major metabolite of menthone in Mentha spp.,918 and a cell-free extract also acetylated menthol.919 Detailed in vivo and in vitro investigations revealed that in leaf discs the bulk of the neomenthol and menthol (produced from menthone) was converted into the gluco- 

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Scheme 26 Conversion of radiolabelled factor III (79) to cobyrinic acid (analyzed as cobester, 75a) and acetic acid by cell-free extracts of P. shermanii and Clostridium tetenomorphum. Labelling patterns = 3H, = 14C or...

The correct catabolic pattern of histidine was established first in bacterial preparations and for this reason will be discussed first. Cell-free extracts of Pseudomonas fluorescens were obtained which catalyze the quantitative conversion of L-histidine to L-glutamic acid, formic acid, and 2 moles of NH3, as required by equation 14. Proof of the formation of L-glutamate was obtained by isolating the crystalline hydrochloride from the incubation mixture and establishing its identity. ... 

The relationship between MAP kinase activity and/or its direct substrates (e.g. p90rsk) and CSF inactivation is unclear. Abrieu and colleagues (1996) found that in cell-free Xenopus eggs extracts MAP kinase remains active when MPF is inactivated. Thus, despite the fact that MAP kinase remains continuously active and phosphorylated, the CSF activity seems to be inactivated. A similar pattern... 

The enzymatic activity in soil is mainly of microbial origin, being derived from intracellular, cell-associated or free enzymes. Only enzymatic activity of ecto-enzymes and free enzymes is used for determination of the diversity of enzyme patterns in soil extracts. Enzymes are the direct mediators for biological catabolism of soil organic and mineral components. Thus, these catalysts provide a meaningful assessment of reaction rates for important soil processes. Enzyme activities can be measured as in situ substrate transformation rates or as potential rates if the focus is more qualitative. Enzyme activities are usually determined by a dye reaction followed by a spectrophotometric measurement. 

The second major breakthrough in understanding the defect in CGD neutrophils came through the development of assays in which the NADPH oxidase can be activated in a cell-free system in vitro ( 5.3.2.3). In these systems, activation of the oxidase can be achieved by the addition of cytoplasm to plasma membranes in the presence of NADPH and arachidonic acid (or SDS or related substances). Interestingly, the oxidase cannot be activated in these cell-free systems using extracts from CGD neutrophils however, cytosol and plasma membranes from normal and CGD neutrophils may be mixed, and in most cases activity is restored if the correct mixing pattern is used. For example, as may be predicted, in X-linked CGD it is the membranes that are defective (because the cytochrome b is deficient), whereas in autosomal recessive CGD the cytosol is defective in the cell-free system. 

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