Invertase active site

The resolvase / invertase family and invertible DNA sequences. A second large family of recombinases act by cleaving a target DNA sequence hydrolytically leaving a free 3 -OH end (Eq. 27-14, step a). This free end then attacks a phosphodiester linkage in a second strand of DNA, cleaving that strand with an in-line nucleophilic displacement (step b). Active sites usually contain a characteristic cluster of aspartate and... 

By contrast, the Dowex-lx8-50 /invertase complex had an IC of 2%, though AI and protein retention were 100%. A reasonable hypothesis for understanding this result might be related to the quite high occurrence of undesirable interactions between the active site and/ or another sensitive domain of the enzyme with charged chemical groups of the resin (11). Such a phenomenon, although with more or less intensity, could also have contributed to the IC variation observed for other Dowex/invertase complexes. 

Investigate the inhibition of the enzymatic reaction by p-mercuribenzoate at concentrations of about 10 M Show how an investigation of inhibition or poisoning of the catalyst might be used to establish the number of catalytically active sites on an invertase molecule. 

Table I 257-283) lists six /3-fructofuranosidases, which have homology with the active site peptide surrounding Asp-42 in yeast invertase 233, 234). Two fructosyltransferases, S. mutans fructosyltransferase and B. subtilis levansu-crase, have extensive sequence homology but are not homologous with the invertase group (255).

Butler have suggested that HA may inhibit pronase activity either by competing with the substrate for the catalytically active sites on the enzyme surface, or by causing conformational changes in the enzyme, resulting in a decreased affinity for the s >strate. In studies involving the enzymes invertase, phosphatase and peroxidase, there was... 

There are scattered reports that phenolic acids inhibit a variety of enzymes, and it is evident that these compounds can block the function of many enzymes if they are sufficiently concentrated at the site of enzymatic functions. Activities of amylase, maltase, invertase, acid phosphatase and protease were suppressed by ferulic acid in tests using maize seeds and seedlings.17,50 Exogenously applied gibberellic acid reversed the effect of ferulic acid on amylase and acid phosphate. 

Genetic modification of P. putida is highly relevant for metabolic engineering of producing strains. Modifications of interest consist of deletions and insertions attributing new features to the genome [66]. Such manipulations can be obtained by (i) homologous recombination (mediated by the RecA catalytic activity), (ii) site-specific recombination (subordinated to either the resolvase-invertase family or the FLP-fRT, Cre-loxP family, also referred to as the Int family), and... 

Crane (1966) has theorized that the brush border plasma membrane is the site of a mosaic of the enzymes associated with the microvillus. This was based on experiments of Eichholz and Crane (1965) who recovered a fraction of pure microvillous membranes by density gradient centrifugation of brush border homogenate which possessed the total activities of alkaline phosphatase, maltas and sucrase and various peptidases. Evidence in favor of this idea was also collected by Johnson (1967) who demonstrated the presence of knobs 60 A in diameter on the glycocalyx of the luminal side of the plasma membrane which contained the brush border invertase and maltase (see Fig. 6). These knobs could be removed entirely from the microvilli of hamster intestine by papain digestion the remaining membrane, however, still has the alkaline phosphatase incorporated into it (Eichholz, 1969 Oda and Seki, 1966). 

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