scholarly journals Purification, properties and cellular localization of the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena

1977 ◽  
Vol 167 (3) ◽  
pp. 723-729 ◽  
Author(s):  
G W J Matcham ◽  
K S Dodgson ◽  
J W Fitzgerald
Keyword(s):  
Chain Length ◽  
Cellular Localization ◽  
Indirect Evidence ◽  
Initial Study ◽  
Potassium Salts ◽  
Experimental Conditions ◽  
Alkyl Sulphate ◽  
A Subunit ◽  
A Chain ◽  
Comamonas Terrigena

The availability of homogeneous samples of the potassium salts of L- and D-octan-2-yl sulphate has enabled the separation of the optically stereospecific CS1 and CS2 secondary alkysulphohydrolases from extracts of cells of Comamonas terrigena. The CS2 enzyme was purified to homogeneity, and an initial study was made of its general properties, specificity, cellular localization and relationship to the CS1 enzyme. The CS2 enzyme has a molecular weight of approx. 250000 and a subunit size of approx. 58000, indicating that the molecule is a tetramer. Under the experimental conditions used the enzyme appears to be specific for (+)-secondary alkyl sulphate esters with the sulphate group at C-2 and with a chain length of at least six carbons. Enzyme activity towards racemic C-2 sulphates increases with increasing chain length up to C10, and there is some indirect evidence to suggest that activity declines when that chain length is exceeded. Other indirect evidence confirms that the CS1 enzyme exhibits similar specificity, except that only (-)-isomers can serve as substrates. Both enzymes are present in broth-grown stationary-phase cells of C. terrigena in approximately equal amounts.

scholarly journals Purification and properties of the S1 secondary alkylsulphohydrolase of the detergent-degrading micro-organism, Pseudomonas C12B

1978 ◽  
Vol 169 (3) ◽  
pp. 659-667 ◽  
Author(s):  
Barbara Bartholomew ◽  
Kenneth S. Dodgson ◽  
Stephen D. Gorham
Keyword(s):  
Chain Length ◽  
Alkyl Chain ◽  
Competitive Inhibitor ◽  
Sulphate Group ◽  
Experimental Conditions ◽  
Alkyl Sulphate ◽  
Purification And Properties ◽  
Crude Preparation ◽  
A Chain ◽  
Comamonas Terrigena

The S1 secondary alkylsulphohydrolase of the detergent-degrading micro-organism, Pseudomonas C12B, was separated from other alkylsulphohydrolases and purified to homogeneity. Under the experimental conditions used the enzyme completely hydrolysed d-octan-2-yl sulphate (d-1-methylheptyl sulphate), but showed no activity towards the corresponding l-isomer. Additional evidence has been obtained to indicate that it is probably optically stereospecific for d-secondary alkyl sulphate esters with the ester sulphate group at C-2 and with a chain length of at least seven carbon atoms. Enzyme activity towards racemic samples of heptan-2-yl sulphate (1-methylhexyl sulphate), octan-2-yl sulphate and decan-2-yl sulphate (1-methylnonyl sulphate) increased with increasing chain length. l-Octan-2-yl sulphate is a competitive inhibitor of the enzyme, as are certain primary alkyl sulphates and primary alkanesulphonates. Inhibition by each of the last two types of compounds is characteristic of the behaviour of an homologous series. Inhibition increases with increasing chain length and plots of log Ki values against the number of carbon atoms in each alkyl chain show the expected linear relationship. A crude preparation of the S2 secondary alkylsulphohydrolase was used to show that this particular enzyme hydrolyses l-octan-2-yl sulphate, but is probably inactive towards the corresponding d-isomer. The similarity of the S1 and S2 enzymes to the CS2 and CS1 enzymes respectively of Comamonas terrigena was established, and some comments have been made on the possible roles of these and other alkylsulphohydrolases in the biodegradation of detergents.

scholarly journals Further studies on the substrate specificity and inhibition of the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena

1980 ◽  
Vol 191 (2) ◽  
pp. 467-473 ◽  
Author(s):  
Carol H. Barrett ◽  
Kenneth S. Dodgson ◽  
Graham F. White
Keyword(s):  
Free Energy ◽  
Chain Length ◽  
Alkyl Chain ◽  
Hydrophobic Interactions ◽  
Standard Free Energy ◽  
Alkyl Chain Length ◽  
Alkyl Sulphate ◽  
Competitive Inhibitors ◽  
Free Energy Of Binding ◽  
Comamonas Terrigena

A series of d-alkan-2-yl sulphate esters (C7–C14) were prepared by sulphation of the resolved parent alcohols by a method that entails complete retention of configuration. These sulphate esters were tested as substrates for the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena. Vmax. reached a maximum with the C9 compound, whereas logKm decreased linearly as the alkyl-chain length was increased from C7 to C14. A parallel series of l-alkan-2-yl sulphates was also prepared, and these esters, together with homologous series of primary alkyl sulphates and primary alkanesulphonates, were shown to be competitive inhibitors of the CS2 enzyme. For each series of compounds, logKi values decreased linearly with increasing alkyl-chain length. Plots of chain length against the standard free energy of binding (ΔG0) of substrate and inhibitors to the CS2 enzyme showed that the standard free energy of association of a –CH2– group with the enzyme was 2.0–2.4kJ/mol for all classes of compound studied, indicating an important contribution from hydrophobic interactions to the overall binding. Plots for d-alkan-2-yl sulphate substrates and primary alkyl sulphate inhibitors were nearly coincident, suggesting that the overall interaction between a primary ester and the enzyme is the same as that between the isomeric secondary substrate and the enzyme. Plots for l-alkan-2-yl sulphate and alkanesulphonate inhibitors were very similar to each other, but were displaced by 1.5–3.0kJ/mol from that for substrate binding. This indicates that the binding of any one of these particular inhibitors involves one carbon atom fewer than the number involved in binding a substrate of the same chain length. These observations are discussed in terms of a three-point attachment of substrate to the enzyme involving the alkyl chain, sulphate group and the C-1 methyl group.

Die Kinetik und der Mechanismus der thermischen Reaktion zwischen Schwefeltetrafluorid und Fluor / The Kinetics and the Mechanism of the Thermal Reaction between Sulfurtetrafluoride and Fluorine

1981 ◽  
Vol 36 (11) ◽  
pp. 1381-1385 ◽  
Author(s):  
Alicia Cristina Gonzalez ◽  
Hans Joachim Schumacher
Keyword(s):  
Chain Length ◽  
Total Pressure ◽  
Reaction Rate ◽  
Thermal Reaction ◽  
Primary Process ◽  
Chain Reaction ◽  
Experimental Conditions ◽  
Medium Length ◽  
A Chain ◽  
Kinetics Of

AbstractThe kinetics of the thermal reaction between SF4 and F2 has been investigated between − 2.4 °C and + 24.0 °C, SF6 and very small amounts of S2F10 being the only products. The reaction is a chain reaction of medium length. Total pressure and surface have only insignificant influence. The reaction rate follows the equation: Under the experimental conditions less than 15% of the SF5 radicals are consumed by r (4b). Therefore Oxygen inhibits the reaction eliminating the SF5 radicals, the final products being now SF5O3SF5 and SF6. From the data obtained in the experiments with high oxygen pressures the rate constant of the primary process and the chain length (v) are determined. E = 10.8 ± 0.7 kcal, E1 = 11.9 ± 0.6 kcal and E4 ≃ 0. E2 = 5.0 ± 2.0 kcal (estimated value) and E3 = 4.7 ± 2.5 kcal.

Effects of absence positioning of unknown product ingredients on consumer evaluations

2018 ◽  
Vol 52 (9/10) ◽  
pp. 2128-2150
Author(s):  
Timucin Ozcan ◽  
Ahmet M. Hattat ◽  
Michael Hair
Keyword(s):  
Regulatory Focus ◽  
Initial Study ◽  
Positive Influence ◽  
Mediation Effect ◽  
Amazon Mechanical Turk ◽  
Initial Attempt ◽  
Experimental Conditions ◽  
Consumer Evaluations ◽  
Content Type ◽  
Study Results

Purpose This paper aims to investigate the effectiveness of positioning unknown ingredients either with the presence or absence of framing; both are common in marketplace (e.g. Secret® deodorant visibly claims “aluminum chlorohydrate” while Crystal® promotes “no aluminum chlorohydrate”). Design/methodology/approach The authors used three scenario-based experiments. The participants were recruited through Amazon Mechanical Turk online panel and randomly assigned to a variety of experimental conditions. Findings Initial study results show that consumers have more positive evaluations and purchase intentions for absence positioning than presence positioning, because absence positioning induces greater perceptions of protection. In the second study, these results are extended using multiple ingredients, along with competitor products; they show that absence positioning leads to better evaluations than presence positioning and replicate the mediation effect that was found earlier. In the final study, through manipulating participants’ regulatory focus, the authors show that absence-positioned ingredients have a higher choice share when consumers are in the prevention mindset. Conversely, when customers are in promotion mindset and looking for better performance, presence positioning of ingredients seems to have higher choice shares. Research limitations/implications The research has implications for product development, promotions, labeling and packaging, showing the positive influence of absence positioning of unknown ingredients. Practical implications Marketers may emphasize the absence of unknown ingredients in their products instead of following a strategy that highlights the inclusion of them. Originality/value To the authors’ extant knowledge, this research is an initial attempt to understand how consumers react to promotion of product ingredients. In addition, it contributes to the literature in unknown attributes by showing that absence positioning of certain types of ingredients is perceived better than presence framing of them.

scholarly journals Iodination of insulin in aqueous and organic solvents

1969 ◽  
Vol 115 (1) ◽  
pp. 11-18 ◽  
Author(s):  
A. Massaglia ◽  
U. Rosa ◽  
G. Rialdi ◽  
C. A. Rossi
Keyword(s):  
Ethylene Glycol ◽  
Organic Solvents ◽  
Molecular Conformation ◽  
Aqueous Media ◽  
Native Structure ◽  
Experimental Conditions ◽  
Polar Environment ◽  
Polar Area ◽  
The Difference ◽  
A Chain

1. The iodination of insulin was studied under various experimental conditions in aqueous media and in some organic solvents, by measuring separately the uptake of iodine by the four tyrosyl groups and the relative amounts of monoiodotyrosine and di-iodotyrosine that are formed. In aqueous media from pH1 to pH9 the iodination occurs predominantly on the tyrosyl groups of the A chain. Some organic solvents increase the iodine uptake of the B-chain tyrosyl groups. Their efficacy in promoting iodination of Tyr-B-16 and Tyr-B-26 is in the order: ethylene glycol and propylene glycol≃methanol and ethanol>dioxan>8m-urea. 2. It is suggested that each of the four tyrosyl groups in insulin has a different environment: Tyr-A-14 is fully exposed to the solvent; Tyr-A-19 is sterically influenced by the environmental structure, possibly by the vicinity of a disulphide interchain bond; Tyr-B-16 is embedded into a non-polar area whose stability is virtually independent of the molecular conformation; Tyr-B-26 is probably in a situation similar to Tyr-B-16 with the difference that its non-polar environment depends on the preservation of the native structure.

scholarly journals The relationship between lymphangion chain length and maximum pressure generation established through in vivo imaging and computational modeling

2017 ◽  
Vol 313 (6) ◽  
pp. H1249-H1260 ◽  
Author(s):  
Mohammad S. Razavi ◽  
Tyler S. Nelson ◽  
Zhanna Nepiyushchikh ◽  
Rudolph L. Gleason ◽  
J. Brandon Dixon
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Minimally Invasive ◽  
Chain Length ◽  
Maximum Pressure ◽  
Computational Simulations ◽  
A Chain ◽  
Lymphatic Pumping ◽  
The Relationship

The intrinsic contraction of collecting lymphatic vessels serves as a pumping system to propel lymph against hydrostatic pressure gradients as it returns interstitial fluid to the venous circulation. In the present study, we proposed and validated that the maximum opposing outflow pressure along a chain of lymphangions at which flow can be achieved increases with the length of chain. Using minimally invasive near-infrared imaging to measure the effective pumping pressure at various locations in the rat tail, we demonstrated increases in pumping pressure along the length of the tail. Computational simulations based on a microstructurally motivated model of a chain of lymphangions informed from biaxial testing of isolated vessels was used to provide insights into the pumping mechanisms responsible for the pressure increases observed in vivo. These models suggest that the number of lymphangions in the chain and smooth muscle cell force generation play a significant role in determining the maximum outflow pressure, whereas the frequency of contraction has no effect. In vivo administration of nitric oxide attenuated lymphatic contraction, subsequently lowering the effective pumping pressure. Computational simulations suggest that the reduction in contractile strength of smooth muscle cells in the presence of nitric oxide can account for the reductions in outflow pressure observed along the lymphangion chain in vivo. Thus, combining modeling with multiple measurements of lymphatic pumping pressure provides a method for approximating intrinsic lymphatic muscle activity noninvasively in vivo while also providing insights into factors that determine the extent that a lymphangion chain can transport fluid against an adverse pressure gradient. NEW & NOTEWORTHY Here, we report the first minimally invasive in vivo measurements of the relationship between lymphangion chain length and lymphatic pumping pressure. We also provide the first in vivo validation of lumped parameter models of lymphangion chains previously developed through data obtained from isolated vessel testing.

scholarly journals LOSS OF PROTEINPOLYSACCHARIDES AT SITES WHERE BONE MINERALIZATION IS INITIATED

1972 ◽  
Vol 20 (4) ◽  
pp. 279-292 ◽  
Author(s):  
D. BAYLINK ◽  
J. WERGEDAL ◽  
E. THOMPSON
Keyword(s):  
Calcium Concentration ◽  
Bone Mineralization ◽  
Bone Matrix ◽  
Indirect Evidence ◽  
Experimental Conditions ◽  
Acid Polysaccharide ◽  
Major Acid ◽  
Tibial Cortex

In both ground sections and demineralized frozen sections of the rat tibial cortex, osteoid but not mature bone matrix stained for proteinpolysaccharides with the Alcian Blue and toluidine blue techniques. The loss of proteinpolysaccharide staining occurred precisely at the mineralizing front, which was identified by in vivo lead or procion markers, not only in normal animals but also in animals in which osteoid width was either increasing or decreasing. In vitro, both proteases and saccharidases abolished proteinpolysaccharide staining of osteoid. Critical electrolyte concentration and other procedures indicated that the major acid polysaccharide component in osteoid is chondroitin sulfate. Consistent with these findings, electron microprobe analyses revealed that sulfur concentration was high in osteoid but dropped abruptly as calcium concentration increased at the mineralizing front. The precise synchronization between loss of proteinpolysaccharides and onset of mineralization under various experimental conditions provides strong indirect evidence that the loss of these macromolecules is somehow involved in initiation of mineralization in bone.

scholarly journals Uremic platelets have a functional defect affecting the interaction of von Willebrand factor with glycoprotein IIb-IIIa

Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1336-1340 ◽  
Author(s):  
G Escolar ◽  
A Cases ◽  
E Bastida ◽  
M Garrido ◽  
J Lopez ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Indirect Evidence ◽  
Flow Conditions ◽  
Experimental Conditions ◽  
Shear Rates ◽  
Functional Defect ◽  
Uremic Patients ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Uremic patients have an impaired platelet function that has been related to membrane glycoprotein (GP) abnormalities. Using a perfusion system, we have studied the interaction of normal and uremic platelets with vessel subendothelium (SE) under flow conditions. Reconstituted blood containing washed platelets, purified von Willebrand factor (vWF) (1 U/mL), and normal washed red blood cells was exposed to de- endothelialized rabbit segments for 10 minutes at two different shear rates (800 and 1,600 seconds-1). In some experiments a monoclonal antibody to the GPIIb-IIIa complex (EDU3) was added to the perfusates. With normal platelets, the percentage of the vessel covered by platelets (%CS) was 23.1% +/- 3.7% at 800 seconds-1 and 30% +/- 4.3% at 1,600 seconds-1. Platelets were observed in contact or forming monolayers on vessel SE. EDU3 inhibited the spreading of normal platelets. The %CS (11.1% +/- 3.3%) was statistically decreased (P less than .01) and most of the platelets were observed in contact with the vessel surface. These data indicate that, under flow conditions, the interaction of vWF with GPIIb-IIIa can support the spreading of normal platelets in the absence of exogenous fibrinogen. Under the same experimental conditions, the interaction of uremic platelets with SE was markedly impaired at both shear rates studied (P less than .01 v normal platelets). The presence of EDU3 did not modify the interaction of uremic platelets. These results confirm the impairment of the platelet adhesion observed in uremic patients. Furthermore, they indicate the presence of a functional defect in the interaction of vWF with GPIIb-IIIa. The fact that perfusions with normal and uremic platelets in the presence of an antibody to the GPIIb-IIIa complex did not show any differences gives indirect evidence on a functionally normal interaction vWF/GPIb in uremic patients.

scholarly journals The mitogenic activities of phosphatidate are acyl-chain-length dependent and calcium independent in C3H/10T1/2 cells.

1991 ◽  
Vol 2 (1) ◽  
pp. 57-64 ◽  
Author(s):  
M J Krabak ◽  
S W Hui
Keyword(s):  
Fatty Acid ◽  
Dna Synthesis ◽  
Chain Length ◽  
Acyl Chain ◽  
Calcium Transient ◽  
Signaling Mechanism ◽  
Acyl Chain Length ◽  
Dose Dependent Fashion ◽  
Continuous Presence ◽  
A Chain

Phosphatidates (PA or phosphatidic acid) were shown to have mitogenic properties, including the stimulation of DNA synthesis and calcium mobilization in C3H/10T1/2 cells. Their continuous presence for a minimum of 7 h induced DNA synthesis with kinetics similar to that observed when 10% fetal bovine serum was used as a mitogen. PAs with long chain saturated fatty acid moieties were more mitogenic, in a dose-dependent fashion, than PAs with short saturated or unsaturated fatty acid moieties. When compared with lysostearoyl-PA (LSPA), distearoyl-PA (DSPA) was as potent with respect to the induction of DNA synthesis. Lysooleoyl-PA (LOPA) was slightly more potent than dioleoyl-PA (DOPA), but much weaker than DSPA and LSPA. Preincubation with dilauroyl-PA (DLPA) reduces the mitogenic effect of DSPA by 85%. The pattern of mitogenic inhibition suggests that a chain-length-independent, yet PA-specific, mechanism is involved. Both DSPA and DLPA are equally taken up by the cells after 30 min. LOPA, but not LSPA, produced a large calcium transient (1.3 microM), which we found to be derived from intracellular sources. DSPA, the most mitogenic PA tested, produced a weaker transient (0.6 microM). Interestingly, LSPA did not produce any detectable calcium transient. These results suggest that the chain-length-specific step in the signaling mechanism of PA occurs after the initial chain-length-independent partitioning and/or binding to the membrane and that the induction of DNA synthesis is not related to the observed calcium transients.

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