Long-chain Primary Alcohols Research Articles

Stereoselective recognition of monolayers of cholesterol, ent-cholesterol, and epicholesterol by an antibody.

The interaction between a monoclonal antibody and four distinct monolayers with varying degrees of structural, chemical, and stereochemical similarity were studied and quantified. The antibody, raised and selected against cholesterol monohydrate crystals, interacts with cholesterol monolayers stereospecifically, but not enantiospecifically. Monolayers of ent-cholesterol molecules, which are chemically identical to cholesterol and whose structure is the exact mirror image of the cholesterol monolayer, interact with the antibody to the same extent as the cholesterol monolayers. The affinity of the antibody for both enantiomeric monolayers is extremely high. However, the antibody does not interact with monolayers of epicholesterol, which is an epimer of cholesterol: The hydroxy group in epicholesterol is in the 3alpha position rather than in the 3beta position, imposing a different angle between the hydroxy group and the rigid steroid backbone, and a different packing of the molecules. Monolayers of triacontanol, a long-chain primary aliphatic alcohol, interact with the antibody to a lesser extent than the cholesterol and ent-cholesterol monolayers, presumably due to the structural flexibility of the triacontanol molecule. The lack of chiral discrimination by the antibody is thus correlated to the level at which the chirality is exposed at the surface of the monolayers.

A New Approach to the IR Spectroscopic Study of Molecular Orientation and Packing in Adsorbed Monolayers. Orientation and Packing of Long-Chain Primary Amines and Alcohols on Quartz

A new method is suggested for determining the molecular orientation in adsorbed films with uniaxial and biaxial anisotropy from two (s- and p-polarized) IRRAS spectra of the same sample, measured at the optimal angle of incidence. The method is simple, does not use the film thickness, and is internally stable with respect to the uncertainty in the input optical parameters of the anisotropic film. The advantages and limitations of the method are discussed. To validate the method, we determined the orientation of hexadecylamine and hexadecyl alcohol adsorbed on a quartz surface. It is shown that at a concentration above the concentration of 2D precipitation but below the concentration of 3D precipitation, hydrocarbon chains in the adsorbed amine monolayer are well-packed in a monoclinic (biaxial) subcell with a tilt angle of about 30°. Chaotically arranged crystallites of the amine molecules appear at the surface at a concentration higher than the concentration of 3D precipitation. Adsorbed monolayers of the alcohol turn out to have a hexagonal structure, in which the hydrocarbon tails are “flip-flop” positioned and tilted by 25−30° from the surface normal.

Phthalocyanine formation using metals in primary alcohols at room temperature

Lithium metal added to a solution of 4-neopentoxyphthalonitrile in 1-octanol or other long-chain primary alcohols at room temperature resulted in phthalocyanine formation at a reasonable rate in good yield, while preformed lithium 1-octanolate under the same conditions gave 2,9,16,23-tetraneopentoxyphthalocyanine, but in lower yield at a slower rate. The use of lower-molecular-weight alcohols slowly gave a phthalocyanine in lower yields. Reverse micelle formation when using long-chain alcohols is proposed as a possibility for enhanced phthalocyanine formation at room temperature. 2,9,16,23-Tetrasubstituted phthalocyanines and metallated phthalocyanines were prepared at room temperature from 4-neopentoxyphthalonitrile, 4-bis(4-methoxyphenyl)methoxyphthalonitrile, 4-[1-(4-ethoxy-3-methoxyphenyl)-1-phenyl]methoxyphthalonitrile and phthalonitrile using lithium 1-octanolate in 1-octanol or by the addition, to a solution of the phthalonitrile in ethanol, of calcium turnings or, to a solution of the phthalonitrile in methanol, of magnesium, zinc, iron or copper powder. The tetrasubstituted phthalocyanines produced exhibited a non-statistical distribution of regioisomers, indicating that electronic effects become important in room-temperature cyclotetramerization of phthalonitriles to phthalocyanines.

The effect of triacontanol on micropropagation of balm, Melissa officinalis L.

Triacontanol, a long-chain primary alcohol was found to be an effective growth regulator in the micropropagation of balm, Melissa officinalis. In both the multiplication and the rooting phase, concentrations of 2, 5, 10 and 20 μg triacontanol per liter were applied. After 4 weeks of culture, the fresh weight of shoots was measured in the multiplication phase and root formation, photosynthetic activity, chlorophyll content and the fresh and dry weights of shoots were analyzed in the root induction phase. In the multiplication phase, 5 μg/l triacontanol was found to be the optimal concentration, while in the rooting phase 2 μg/l was the most effective. Triacontanol increased the number and length of roots, and it enhanced shoot growth, fresh weight, and the chlorophyll content, but it had no effect on the dry weight and the photosynthetic activity of the plants. Results of our work demonstrate that triacontanol can be applied as an effective growth regulator in the tissue culture of balm.

Engineering yeast alcohol dehydrogenase. Replacing Trp54 by Leu broadens substrate specificity.

Analysis of a crystal structure of alcohol dehydrogenase (Adh) from horse liver suggests that Trp54 in the homologous yeast alcohol dehydrogenase prevents the yeast enzyme from efficiently catalysing the oxidation of long-chain primary alcohols with branching at the 4 position (e.g. 4-methyl-1-pentanol, cinnamyl alcohol). This residue has been altered to Leu by site-directed mutagenesis. The alteration yields an enzyme that serves as an effective catalyst for both longer straight-chain primary alcohols and branched chain alcohols.

The lipid composition of the wax particles from adult whiteflies, Bemisia tabaci and Trialeurodes vaporariorum

Adult whiteflies are characterized by the presence of copious amounts of wax particles covering all surfaces of the body except the eyes. The lipid composition was determined for wax particles removed from the surfaces of the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). The lipid components in the wax particles of both species were mostly mixtures of long-chain aldehydes and long-chain primary alcohols. The major wax particle components for B. tabaci were C 34 aldehyde and C 34 alcohol and small amounts of C 32 aldhyde and alcohol. For the wax particles from T. vaporariorum, C 32 aldehyde and C 32 alcohol were the major components with lesser amounts of the C 30 components. These findings were compared to the surface lipids of fully-waxed B. tabaci and T. vaporariorum adults that contained, in addition to the major amounts of long-chain aldehydes and alcohols, quantities of long-chain wax esters. Wax esters were not present in lipid extracts from the surface of B. tabaci whiteflies at the time of adult emergence (prior to deposition of wax particles). Thus, the appearance of wax esters on the cuticular surfaces occurred during the period of deposition of wax particles. The quantities of wax esters in the surface lipid extracts of wing tissues separated from the bodies of adult whiteflies indicated that the wing surfaces were a major site of wax ester deposition.

1,16-Hexadecanediol, C16H34O2

The crystal structure of the title compound was determined by X-ray diffraction. The skeleton of the molecule is all trans and the molecules form a layer structure along the b axis as in a long-chain primary alcohol or a smectic C liquid crystal. The inclination angle of the long axis of the molecule to the layer plane is equal in each layer, but the direction of the long axis is opposite in alternate layers. This arrangement is different from that of the long-chain primary alcohols

Dielectric Studies on Binary Mixtures of Tri-n-butyl Phosphate (TBP) and Long-Chain Primary Alcohols (Modifiers)

Dielectric constant (ε) of Tri-n-butyl phosphate (TBP), in binary mixtures with five long-chain primary alcohols viz; 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol has been measured at ν=455 kHz and at temperature 302 K. The data is used to evaluate mutual correlation factor gab, excess molar polarization ΔP and excess free energy of mixing ΔFab by using Winkelmann-Quitzsch eqn. for binary mixtures to assess the suitability of the alcohols as modifiers. The trend of variation of these parameters exhibit marked dependence on chain-length of the alcohols indicating 1-heptanol to be an efficient modifier.

Reversible enzymatic transesterification between wax esters and sterols in Sinapis alba roots

Young roots of mustard ( Sinapis alba) contain a membrane-bound acyltransferase which catalyses esterification of cholesterol by direct transfer of acyl groups from fatty acid esters of long-chain primary alcohols (wax esters) or esterification of n-hexadecanol with the use of steryl esters as fatty acid sources. Acyl transfer from cholesteryl esters to free cholesterol or from n-hexadecanyl esters to n-hexadecanol can be also observed with this enzyme. The acyltransferase is located in the membranous structures sedimenting at 16 000 g but can be solubilized by acetone treatment and extraction with Tris-maleate, pH 7.3. With the solubilized enzyme the esterification of cholesterol, with n-hexadecanyl palmitate as the acyl source, showed two pH optimaat pH 6.4 and 8.4. In this reaction the best acyl donor among n-hexadecanyl esters varying in the fatty acid moiety was n-hexadecanyl palmitate. Our results suggest that the lsquo;low energy’ exchange of acyl groups may be of importance for steryl ester or/and wax ester synthesis in higher plants.

Anomalous concentrations of specific alkylaromatic and alkylcycloparaffin components in West Texas and Michigan crude oils

Crude oils produced from a Midland Basin, West Texas reservoir and a Michigan Basin reservoir contain anomalous concentrations of specific members in several alkylaromatic and alkylcyclohexane, homologous series. These components include C 15-alkylated benzene, toluene, xylene, cyclohexane, methylcyclohexane, and dimethylcyclohexane; C 11-alkylated napthalene, methylnapthalene, and tetralin; and C 12-alkylated indane. All compounds have been identified by GC-MS analysis of the oils and separated fractions. In nearly all cases, these anomalous components are several times more abundant than their adjacent homologs, as shown by mass fragmentograms. The consistent domination of C 15-alkylated species through the substituted benzene ( m/ z 92), toluene ( m/ z 106) and xylene ( m/ z 119) series in both oils suggests that these components were all derived from alkylation by a n-C 15 group rather than through ring closure of a higher carbon number compound. The same relationships were observed among alkycyclohexanes as well as alkylbenzenes in the Michigan oil; it showed an additional dominance of C 17-alkylated single ring components. However, the dominant C 11-alkyl substitutent in alkylnapthalenes, alkyl-methylnaphthalenes, and alkyltetralins, plus a dominance of C 12-alkylindane suggest the second ring is formed by ring closure of a C 15-alkylated single ring compound. A series of heating experiments designed to simulate naturally-occurring reactions demonstrated that benzene, toluene, and cyclohexane can be alkylated by long-chain primary alcohols in the presence of kerogen. The effect of kerogen on alkylation appears to be more relevant to the formation of anomalous alkylated species than does the effect of catalytically-active clays.

7-Oxopentadecan-2-ol esters— A new epicuticular wax lipid class

The alkan-1-ol and alkan-2-ol esters (primarily, C38−C48 and C33−C35, respectively) of barley epicuticular waxes are known to arise via two different biosynthetic pathways. Herein we identify a third type of ester (approx. 0.2% by weight of spike wax), hitherto unknown in these plant lipids. The esters were isolated via preparative TLC together with the longer chain primary alcohols. From the effects of chemical treatments analyzed with the aid of TLC and GC, the presence of an oxo group in the alcohol moiety was deduced. GC-MS of the esters and their alcohol moieties before and after NaBH4 treatment plus of the fatty acid moieties resulted in the identification of at least three 7-oxopentadecan-2-ol esters (C33, 35 and37). 2,7-Dihydroxypentadecane was synthesized and its mass spectrum found to be identical to that of the reduced ester alcohol moiety. A determination of the relative amounts of these esters in ten different genotypes supports the contention that biosynthetically the pentadecan-2-ol esters are precursors of those containing an oxo group on carbon 7.

Quantification of the concentration of aliphatic alcohols by an infrared technique

A quantitative infrared assay for long-chain primary aliphatic alcohols in the presence of oil is described. Absorbances of samples dried for 24 h in vacuo over phosphorus pentoxide and dissolved in trichlorotrifluoroethane, are measured in a 10-mm Infrasil cuvette between 4 000 and 3 000 cm–1. Absorbance for the O–H bond stretching is measured at 3 660 cm–1 in dilute solutions (concentrations below 0.05 M). The presence of oil reduces the response, but this effect can be eliminated provided that the final concentration of the oil is less than 0.5%m/m and that it is counterbalanced by the reference solution.

Influence of long-chain primary alcohols on cholesterol oxidase from Schizophyllum commune

Cholesterol oxidase (cholesterol:oxygen oxidoreductase, EC 1.1.3.6) from Schizophyllum commune was activated and stabilized by the presence of long-chain primary alcohols. There exists a correlation between the degree of activation and the chain-length of alcohols. In the presence of decanol or undecanol maximum activation was observed, while shorter or longer alcohols were less effective. By comparing the effect of alkanes, amines and acids with that of alcohols, the hydroxy group was found essential for the activation. The presence of 0.5% undecanol caused a large change in both the maximum activity and the affinity for substrate, e.g., for cholesterol as substrate V max increased 6.2-fold, while K m increased 10-fold. Binding of undecanol to cholesterol oxidase rendered the structure of the enzyme more compact, as indicated by the increase in α-helix content from 34% in the absence of undecanol to 43% in the presence of undecanol. Sodium dodecyl sulfate at 0.2 mM could stabilize the enzyme but could not enhance the activity at all. Addition of either undecanol or SDS increased the fluorescence intensity ascribable to tryptophan residues of the enzyme. On the other hand, the stabilizing effect of SDS was not observed in the N-bromosuccinimide-modified enzyme. These facts strongly suggest an important role of three to four tryptophan residues in the binding of undecanol with the enzyme.

Assay and properties of the enzyme catalyzing the biosynthesis of 1- O-alkyl dihydroxyacetone 3-phosphate

The properties of the enzyme alkyl dihydroxyacetone phosphate synthase (1- O-acyl dihydroxyacetone 3-phosphate + ROH → 1- O-alkyl dihydroxyacetone 3-phosphate + fatty acid) in Ehrlich ascites tumor cell microsomes were studied utilizing a new assay procedure. The assay is based on the difference of partition coefficient between alkyl dihydroxyacetone- P and hexadecanol in an alkaline two-phase CHCl 3-methanol-water system. The product of the enzymatic reaction was characterized by different methods as alkyl dihydroxyacetone- P. At optimum concentration of the substrates (acyl dihydroxyacetone- P and hexadecanol), detergents or Mg 2+ and ATP do not stimulate the reaction. The kinetic properties of the reaction were found to be complex due to the stimulation of enzyme activity at low acyl dihydroxyacetone- P concentration but inhibition at the high concentration of the same substrate. The enzyme accepts a variety of long-chain primary alcohols as substrate without much specificity. With different acyl dihydroxyacetone- P, the highest activity was obtained with hexadecanoyl (16:0) dihydroxyacetone- P, with somewhat less activity with longer octadecanoyl (18:0) and much less (40% of 16:0) activity with tetradecanoyl (14:0) dihydroxyacetone- P. Preliminary studies indicate that a Schiffs base intermediate of the enzyme with the keto substrate is probably not formed, since NaBH 4 inhibited the enzyme to the same extent in the presence or absence of acyl dihydroxyacetone- P. Fatty acids inhibit the reaction and an exchange of fatty acid with acyl dihydroxyacetone- P in the presence of the enzyme preparation was observed. Heat-inactivation studies indicate that alkyl dihydroxyacetone- P synthase is probably also catalyzing this fatty acid exchange reaction. Based on these findings, an enzyme-bound dihydroxyacetone- P intermediate is proposed.

ChemInform Abstract: N‐ALKYL‐2‐PYRROLIDONES AS DERIVATIVES FOR THE STRUCTURE ELUCIDATION OF LONG‐CHAIN PRIMARY ALCOHOLS BY MASS SPECTROMETRY

AbstractDie prim. Alkohole (I) werden in die Pyrrolidone (II) übergeführt.

Kinetics and reaction mechanism of yeast alcohol dehydrogenase with long-chain primary alcohols

Kinetic studies of yeast alcohol dehydrogenase with NAD+ and ethanol, hexanol or decanol as substrates invariably result in non-linear Lineweaver-Burk plots if the alcohol is the variable substrate. The kinetic coefficients determined from secondary plots are consistent with an 'equilibrium random-order' mechanism for extremely low alcohol concentrations and for all alcohols, the transformation of the ternary complexes being the rate-limiting step of the reaction. This mechanism also applies to long-chain substrates at high concentrations, whereas the rate of the ethanol-NAD+ reaction at high ethanol concentrations is determined by the dissociation of the enzyme-NADH complex. The dissociation constants for the enzyme-NAD+ complex and for the enzyme-alcohol complexes obtained from the kinetic quotients satisfactorily correspond to the dissociation constants obtained by use of other techniques. It is suggested that the non-linear curves may be attributed to a structural change in the enzyme itself, caused by the alcohol.

Ether lipid metabolism: Incorporation of O-hexadecyl ethanediol into rat brain lipids

1- O-[1'- 14 C]Hexadecyl ethanediol was administered intracerebrally to myelinating rat brain, and incorporation of radioactivity into brain lipids was followed over a 48-h period: 1. (1) O-Hexadecyl ethanediol was metabolized primarily through oxidative ether bond cleavage, and much of the label was recovered in phospholipid acyl groups. 2. (2) Substantial amounts of radioactivity were also found in choline and ethanolamine phospholipids having an O-hexadecyloxyethyl glycerol backbone. This means that alkyl ethanediol was used in glycerol ether biosynthesis as are long-chain primary alcohols. 3. (3) Acidic hydrolysis of the ethanolamine glycerophosphatide fraction yielded also labeled hexadecanol which may indicate desaturation of 1- O-hexadecyloxyethyl 2-acyl glycerophosphoryl ethanolamine to the plasm alogen analogue. 4. (4) Small amounts of the substrate were oxidized to O-hexadecyl glycolic acid and incorporated into the phospholipids. The substrate did not serve as precursor of O-hexadecyl ethanediol phosphorylcholine or phosphorylethanolamine in the brain.

Action of rat pancreatic juice and of purified pig pancreatic lipase upon the esters of short-chain aliphatic mono-acids and long-chain primary monoalcohols

Emulsions of unsubstituted monoesters of long-chain primary alcohols and short-chain aliphatic acids (containing one to four carbon atoms) were attacked by rat pancreatic juice or pure porcine pancreatic lipase. Hydrolysis rates ( V) were measured and compared. The results obtained with the two enzyme preparations are very similar. Observed hydrolysis rates decrease from butyrates to propionates, and decrease still more to acetates. The small hydrolysis rate previously reported for triacetin does not seem attributable to the physical properties of this compound. It is rather the result of a slow action of pancreatic lipase upon the esters of acetic acid in general. Formates of long-chain primary alcohols are hydrolyzed much faster than acetates, almost as fast as butyrates. Some comparisons were attempted between the behaviour, towards lipase, of long-chain fatty acid, short-chain alcohol monoesters and of short-chain fatty acid, long-chain alcohol monoesters. In both series, a distinct minimum for the hydrolysis rate is apparent when the small group in the ester molecule contains two carbon atoms (acetyl or ethyl groups). Competitive experiments upon ester mixtures suggest that the differences observed for the lipolysis rates of insoluble esters are not explained by a lack of affinity of lipase for some of these compounds. The esters which are slowly hydrolyzed seem to bind to lipase somewhat more firmly than those which react fast. As an example, the affinity of lipase for hexadecyl formate seems a little higher than for triolein. The possible role of an S N2 mechanism and of hydrophobic bonding in lipase reactions is briefly discussed.

Separation and characterization of long-chain alcohol dehydrogenase isoenzymes from Pseudomonas aeruginosa

1. 1. A NADP-dependent alcohol dehydrogenase (alcohol dehydrogenase I) from Pseudomonas aeruginosa was stabilized by glycerol and purified by chromatography on DEAE-cellulose and hydroxyapatite. 2. 2. This purification also permitted the separation of other isoenzymes: (a) A second minor NADP-dependent alcohol dehydrogenase (alcohol dehydrogenase II). (b) A NAD-dependent alcohol dehydrogenase fraction (Fraction III). 3. 3. Kinetic properties of alcohol dehydrogenase I, alcohol dehydrogenase II and Fraction III have been compared with those of alcohol:NAD + oxidoreductase (EC 1.1.1.1.) from yeast. 4. 4. Alcohol dehydrogenase I and alcohol dehydrogenase II had a high affinity (low K m values) for long-chain primary alcohols. 5. 5. A study of Fraction III strongly suggested the presence of two enzymes, one for lower alcohols, the other one with a good affinity for higher alcohols. Further purification work on Fraction III resulted but in partial separation of these enzymes.

The Synthesis of Some Long-chain Primary Alcohols and Related Compounds1

The Synthesis of Some Long-chain Primary Alcohols and Related Compounds¹