Candida Cationic

Although [BMIM]BF4 has been evaluated as an isolation medium for lipase-catalyzed biotransformations, the general experience with it has not been favorable, relative to that with other ionic liquids, such as [BMIM]PF6. However, excellent performance was recently reported for [BDMIM]BF4 when it was used to host Candida antarctica (Novozym 435) for the enantioselective transesterification of 5-phenyl-l-penten-3-ol (+ and -) with vinyl acetate. The working hypothesis was that the oligomerization of acetaldehyde may be caused by the C2 proton of the [BMIM] ion because of the unfavorable acidity of this group (226). In contrast, the cation in [BDMIM]BF4 lacks this acidity. 

In Fig. 3.8, examples are presented of structures representing the main classes of dyes used for antimicrobial PDT. The most investigated among them are cationic porphyrin derivatives (Alves et ah, 2009). They were shown to be effective in the killing of both Gram-positive and Gramnegative bacteria in suspension as well as in biofilms (Demidova and Hamblin, 2004 Di Poto et ah, 2009). Yeast cells Candida albicans) were also shown to be susceptible to photod)mamic inactivation when treated with tri- and tetracationic porphyrin derivatives (Cormick et ah, 2009). 

In contrast to the FDPases isolated from mammalian tissues, which are active with both FDP and SDP, the enzyme in Candida utilis is completely specific for FDP. A second activity, which catalyzes the hydrolysis of SDP to S7P, has been purified from this organism. The specific SDPase differs from the FDPase in lacking the requirement for the divalent metal cation and in showing optimum activity at neutral pH. Recently, the presence of distinct FDP and SDPases in this organism has been confirmed by the separation of these enzymes in phospho-cellulose chromatography and by the isolation of each enzyme in pure form (84). The purified FDPase and SDPase were found to differ in molecular weight and amino acid composition. 

Fraenkel et al. (17), who isolated mutant strains which had lost the ability to grow on glycerol, succinate, or acetate but grew normally on hexoses or pentoses. These organisms were shown to be deficient in a specific FDPase, which could be distinguished from the nonspecific acid hexosephosphatase present in both mutant or wild-type strains by the fact that the latter was present in the periplasmic space (86) and did not require a divalent metal cation. The properties of the specific FDPase were confirmed with a partially purified preparation (87) the E. coli enzyme was shown to be highly specific for FDP and to be active with very low concentrations of this substance. The requirement for a divalent cation was satisfied by Mg2+, which was far more effective than Mn2+ other divalent cations were either inactive or inhibitory. The partially purified enzyme showed optimum activity at pH 7.8, with very little activity below pH 7 or above pH 9. The enzyme resembled mammalian and Candida FDPases in its sensitivity to low concentrations of AMP it was approximately 50% inhibited at an AMP concentration of 2.5 X 10-° M. 

Surprisingly, the MICs for Candida of a variety of cationic structural analogues were only roughly correlated with the enzyme inhibition and animal efficacy data. The most potent compounds had lower MICs than the less effective ones, but the relative ranking could not predict in vivo efficacy for all compounds. As more data accumulated from the medicinal chemisny effort, it became clear that the in vitro enzyme data for the Candida enzyme constituted the best predictor of in vivo activity. 

Adsorption of enzymes to various polymeric resins is a straightforward means for immobilization. Zwitterionic molecules such as proteins can bind to both anionic and cationic ion exchange resins. Hydrophobic macroporous resins are also useful for immobilizing many enzymes, particularly lipases. For example, an immobilized form of Candida antarctica lipase B (CAL-B) on acrylic resin has been sold for many years under the name, Novozym 435 (N435). The enzyme is produced in a modified Aspergillus organism by submerged fermentation and is subsequently adsorbed onto a macroporous... 

So far, only very little attention has been focussed on the use of zeolites in biocatalysis, i.e., as supports for the immobilization of enzymes. Lie and Molin [116] studied the influence of hydrophobicity (dealuminated mordenite) and hydrophilicity (zeolite NaY) of the support on the adsorption of lipase from Candida cylindracea. The adsorption was achieved by precipitation of the enzyme with acetone. Hydrolysis of triacylglycerols and esterification of fatty acids with glycerol were the reactions studied. It was observed that the nature of the zeolite support has a significant influence on enzyme catalysis. Hydrolysis was blocked on the hydrophobic mordenite, but the esterification reaction was mediated. This reaction was, on the other hand, almost completely suppressed on the hydrophilic faujasite. The adsorption of enzymes on supports was also intensively examined with alkaline phosphatase on bentolite-L clay. The pH of the solution turned out to be very important both for the immobilization and for the activity of the enzyme [117]. Acid phosphatase from potato was immobilized onto zeolite NaX [118]. Also in this study, adsorption conditions were important in causing even multilayer formation of the enzyme on the zeolite. The influence of the cations in the zeolite support was scrutinized as well, and zeolite NaX turned out to be a better adsorbent than LiX orKX. 

B Ahlstrom, M Chehninska-Bertilsson, RA Thompson, L Edebo. SubmiceUar complexes may initiate the fungicidal effects of cationic amphiphilic compounds on Candida albicans. Antimicrob Agents Chemother 41(3) 544-550, 1997. 

Tabli 9 Enzyme Inhibition Minimum Fungicidal Concentrations that Inhibited 90% o/ Fungal Growth (MFCgg) of Species of Candida, and Effective Dose Allowing 50% Survival (ED l of C. albicanj-Infected Mice of Three Cationic Pneumocandins. 

The peracid salt may be used as a general purpose disinfectant, disinfectant for hospitals, food industry and institutions. It is compatible with many nonionic, cationic, anionic and amphoteric surfactants. Recommended use concentrations for the treatment of surfaces according to tests with Enterococcus faecium. Pseudomonas aeruginosa, Staphylococcus aureus,. Proteus mirabilis, Candida albicans (source LONZA) 0.5% (60min) for clean surfaces, 1.0% (60 min) for dirty surfaces... 

Recently, Burney and Pfaendtner [120] reported results from MD simulations of Candida rugosa lipase in two ILs ([bmim]PFj and [bmim]N03).The analysis showed a strong interaction between the protein surface and IL anions due to a broader spatial distribution of positively charged protein residues and reduced mobility of the cation due to the size of the imidazolium ring. 

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