Three new alpha-glucosidase inhibitors, schulzeines A-C (1-3), were isolated from the marine sponge Penares schulzei. Their structures were elucidated by spectral analysis and chemical degradations to be the isoquinoline alkaloids, encompassing two amino acids, and C(28) fatty acid, the last of which was sulfated. Absolute stereochemistry of schulzeines was determined ...

As potential lead structures for a new class of glycosidase inhibitors the novel O-glycosyl amino acid mimetics 3'-O-[2,6-anhydro-D-glycero-L-gluco-heptitol-1-yl]-L-serine 3 and-L-threonine 4 were synthesized, employing regio- and stereoselective aziridine ring opening methodology. They proved to be stable in the presence of glycosidases and showed competitive inhibition of alpha-galactosidase from Aspergillus niger.

Learning disability is a common feature of patients affected by maple syrup urine disease (MSUD). However, the pathomechanisms underlying learning deficit in this disorder are poorly known. In the present study, we investigated the effect of acute administration of the alpha-keto acids accumulating in MSUD into the hippocampus on the ...

AIMS: To examine the effect of alpha-ketoglutaric acid (alpha-KG) on the utilization and catabolism of amino acids by strains of nonstarter lactobacilli isolated from Cheddar cheese. METHODS AND RESULTS: The effect of alpha-KG in the growth medium of nonstarter lactobacilli on amino acid metabolism, catabolite levels, peptide hydrolase and aminotransferase ...

Supplement effects of ions, sugars, and amino acids on the thermostability of liquefying type alpha-amylase from Bacillus subtilis were examined. The addition of 1 mmol/L Ca2+ or about 50 mmol/L Na+ remarkably stimulated the thermostability of this enzyme among ions examined. The thermostability of the enzyme was enhanced and reduced ...

Within this study an oral sustained release dosage form of alpha-lipoic acid (thioctic acid) has been generated and evaluated in healthy volunteers. A granulate comprising 56.8% alpha-lipoic acid and 43.2% chitosan acetate was compressed to tablets (weight: 0.45 g; diameter: 10.0 mm; thickness: 4 mm). Three of these tablets were ...

BACKGROUND: Phytoestrogens offer a possible alternative to hormone replacement therapy. Flax seed contains large quantities of a phytoestrogen precursor, secoisolariciresinol diglucoside (SDG), as well as large quantities of alpha-linolenic acid; these factors may be protective against vascular disease. We have previously shown that the rise in blood pressure during mental ...

There is some evidence that alpha-linolenic acid might be positively related to prostate cancer risk. Associations between serum fatty acid composition as well as fatty acid intakes and prostate cancer risk were examined in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The cohort included 29,133 male smokers aged 50-69 years. During ...

BACKGROUND & AIMS: Although considerable effort has been directed toward the mapping of peptide epitopes by autoantibodies, the role of nonprotein molecules has been less well studied. The immunodominant autoantigen in primary biliary cirrhosis (PBC), E2 components of pyruvate dehydrogenase complexes (PDC-E2), has a lipoate molecule bonded to the domain ...

Neurological dysfunction is a common finding in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathology of brain damage in this disorder are poorly known. In the present study, we investigated the effect of the in vitro effect of the branched chain alpha-keto acids (BCKA) accumulating ...

Various microorganisms, belonging to the genera Lactococcus, Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Propionibacterium, Brevibacterium, Corynebacterium and Arthrobacter, used in dairy fermentations such as cheese making, were analysed for their potential to convert leucine into flavour components, most notably 3-methylbutanal. A large variation between and within species was observed for various enzyme ...

Alpha-(N-substituted amino)esters were prepared in a two-step procedure from available unsubstituted alpha-amino esters. alpha-Amino esters are first converted into the corresponding N-benzotriazolylmethyl derivatives; in the second step, the benzotriazole group is substituted by various nucleophiles with or without the presence of a Lewis acid to give substituted alpha-amino esters in ...

Bjerkandera adusta produces many chlorometabolites including chlorinated anisyl metabolites (CAMs) and 1-arylpropane-1,2-diols (1, 2, 3, 4) as idiophasic metabolic products of L-phenylalanine. These diols are stereoselectively biosynthesized from a C7-unit (benzylic, from L-phenylalanine) and a C2-unit, of unknown origin, as predominantly erythro (1R,2S) enantiomers. Of the labeled amino acids tested ...

R(+)-alpha-lipoic acid is a natural occurring compound that acts as an essential cofactor for certain dehydrogenase complexes. The redox couple alpha-lipoic acid/dihydrolipoic acid possesses potent antioxidant activity. Exogenous racemic alpha-lipoic acid orally administered for the symptomatic treatment of diabetic polyneuropathy is readily and nearly completely absorbed, with a limited absolute ...

Optically active syn-alpha-amidoalkylphenyl sulfones can be prepared from chiral aldehydes in anhydrous conditions using benzenesulfinic acid. These sulfones in basic conditions give N-acylimines that react with sodium methanenitronate to afford the corresponding nitro adducts with high anti diastereoselectivity. PM3 semiempirical calculations provide a rationale for the observed opposite stereoselectivity. The ...

Deprenyl and benzofenone-type congeners of alpha-mangostin 1 have been synthesized to understand their role for the inhibitory activity against sphingomyelinase (SMase). While removal of the prenyl group of the right side (11 and 12) caused loss of the selectivity between ASMase (acidic sphingomyelinase) and NSMase (neutral sphingomyelinase), the prenyl group ...

Aspergillus kawachii produces two kinds of alpha-amylase, one is an acid-unstable alpha-amylase and the other is an acid-stable alpha-amylase. Because the quality of the shochu depends strongly on the activities of the alpha-amylases, the culture conditions under which these alpha-amylases are produced were examined. In liquid culture, acid-unstable alpha-amylase was ...

Rhodococcus sp. strain MS11 was isolated from a mixed culture. It displays a diverse range of metabolic capabilities. During growth on 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) and 3-chlorobenzoate stoichiometric amounts of chloride were released. It also utilized all three isomeric dichlorobenzenes and 1,2,3-trichlorobenzene as the sole carbon and energy source. Furthermore, the ...

A pathogen-induced oxygenase showing homology to prostaglandin endoperoxide synthases-1 and -2 was recently characterized by in vitro experiments as a fatty acid alpha-dioxygenase catalyzing formation of unstable 2(R)-hydroperoxy fatty acids. To study the activity of this enzyme under in vivo conditions and to elucidate the fate of enzymatically produced 2-hydroperoxides, ...

Parkinson's disease is characterized by the aggregation of alpha-synuclein into filamentous forms within affected neurons of the basal ganglia. Fibrillization of purified recombinant alpha-synuclein is inefficient in vitro but can be enhanced by the addition of various agents including glycosaminoglycans and polycations. Here we report that fatty acids and structurally ...

alpha,alpha-Diphenyl-L-prolinol derivatives with para-bromo substituents in either one or both of the phenyl rings are easily bound to crosslinked polystyrene beads containing phenylboronic acid residues by Suzuki couplings. By using extended reaction periods boronic acid residues that do not take part in the couplings are simply lost by hydrolysis. The ...

The enantiopure Davis' N-sulfinylimines were found to be efficient as chiral imine equivalents in the high-temperature Reformatsky-type additions with BrZnCF(2)COOEt affording an efficient approach to the enantiomerically pure alpha,alpha-difluoro-beta-amino acids. High chemical and stereochemical yields (drs > 9:1, and as high as 99:1) render this method immediately useful for preparing ...

We examined the effects of human alpha(1)-acid glycoprotein on isometric tension of mouse aortic rings. alpha(1)-Acid glycoprotein (7.5-75 microM) produced a transient, concentration-dependent relaxation of the phenylephrine-precontracted preparation. Although N(G)-nitro-L-arginine methyl ester or removal of endothelium rarely affected the alpha(1)-acid glycoprotein-induced relaxation, extracellular heparin inhibited the alpha(1)-acid glycoprotein-induced relaxation. In ...

3 Beta-hydroxy-5-cholestenoic acid, 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acid are metabolites of cholesterol present at significant concentrations (40-80 ng/ml) in human circulation. The 7 alpha-hydroxylated acids may be formed from cholesterol via two major pathways initiated by oxidations at either the 7 alpha- or 27-positions. In an attempt ...

Oxidative stress causes metabolic and structural abnormalities during reperfusion. In an animal model of electrophysiological evaluation of cerebral ischemia-reperfusion, alpha-lipoic acid effect on the oxidative stress was studied by mean absolute amplitude of EEG spectra evaluation. The left carotideal infusion of 3.03 mM alpha-lipoic acid in Wistar rats after cerebral ...

To study the formation of fumonisin artifacts and the binding of fumonisins to matrix components (e.g., saccharides and proteins) in thermal-treated food, model experiments were performed. Fumonisin B(1) and hydrolyzed fumonisin B(1) were incubated with alpha-d-glucose and sucrose (mono- and disaccharide models), with methyl alpha-d-glucopyranoside (starch model), and with the ...

The synthesis of a new amphiphilic antioxidant called PBNLP and derived from both alpha-phenyl-N-tert-butyl nitrone (PBN) and lipoic acid was described. Grafting a lactobionamide moiety onto the aromatic group of the PBN provided the water solubility of this compound. In vitro preliminary biological evaluations of its antioxidant capacity were performed ...

A novel and versatile strategy for the synthesis of heterocyclic alpha-amino acids has been described. The use of components (aldehyde or beta-ketoester) bearing a masked glycinyl moiety in Biginelli and Hantzsch cyclocondensations allowed access to the 4-dihydropyrimidinyl-alpha-glycines, 4-dihydropyrimidinyl-alpha-alanines, 4-pyridyl-alpha-alanines, and 2-pyridyl-alpha-alanines classes. Dihydropyrimidinyl-amino acids were obtained as a mixture of ...

alpha-Tosyloxyketones and alpha-tosyloxyaldehydes were directly prepared from alcohols by treatment with iodosylbenzene and p-toluenesulfonic acid monohydrate in good yields. This method can be used for the direct preparation of thiazoles, imidazoles, and imidazo[1,2-a]pyridines from alcohols in good to moderate yields by the successive treatment with iodosylbenzene and p-toluenesulfonic acid monohydrate, ...

Raman and SERS spectra of phenylacetic acid and alpha-phenylglycine on silver sols have been recorded at several concentrations and pH values. The alpha-phenylglycine has been also studied in D(2)O. The respective vibrational assignments have been proposed and the analysis of the SERS spectra has made it possible to conclude that ...

Glucuronidation, a major metabolic pathway for a large variety of endobiotics and xenobiotics, is catalyzed by enzymes belonging to the UDP-glucuronosyltransferase (UGT) family. Among UGT enzymes, UGT2B4 conjugates a large variety of endogenous and exogenous molecules and is considered to be the major bile acid conjugating UGT enzyme in human ...

Two new analogues of 1-D-1-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-myo-inositol, a biosynthetic intermediate in the production of mycothiol in the Mycobacteria have been synthesized. Both the 2-deoxy-2-C-(2'-hydroxypropyl)-D-glucoside 5, and the 2-deoxy-2-C-(2'-oxopropyl)-D-glucoside 6, are derived from fully benzylated 1-D-1-O-(2-C-allyl-2-deoxy)-D-glucopyranosyl)-myo-inositol 20, readily assembled via a protected 2-C-allyl-2-deoxyglucosyl fluoride. Both 5 and 6 inhibit the incorporation of [3H]inositol ...

We have characterized the effects of cinnamic acid and its derivatives on alpha(1)-adrenoceptor subtypes. The cinnamic acid with a methoxyl group and/or a hydroxyl group showed the ability to stimulate radioactive glucose uptake into C(2)C(12) cells, a cell line that specifically expresses the alpha(1A)-adrenoceptor subtype of alpha(1)-adrenoceptors. However, cinnamic acid ...

A film of alpha-naphthalene sulfonate-doped polypyrrole/poly(methylmethacrylate), PPy/alpha-NS(-)/PMMA, obtained from solution mixing was successfully used as sensing material for acetone vapor in lacquer with a high degree of selectivity based on electrical conductivity over acetic acid and a high degree of stability over the humidity change. Compared with pure PPy/alpha-NS(-), the ...

N-phosphorylamino acids are chemically active species that have many biomimic activities. alpha-COOH in amino acids and peptides behaviors rather differently than beta-COOH in many biochemical processes and takes a more important role in the origin of life. Activity differences between alpha-COOH and beta-COOH in the peptide formation of phosphoryl amino ...

The pH-rate profiles for the hydrolysis of uridine 5'-diphospho-alpha-D-glucose (UDPG) and uridine 5'-diphospho-alpha-D-glucuronic acid (UDPGA) in aqueous solution have been measured. The results obtained and a comparison with other data suggests that the mechanism of hydrolysis of each activated glycosyl-donor at pH 1-4 probably involves the slow ionisation, via an ...

BACKGROUND: The degree of branching and types of fucosylation of glycans on alpha(1)-acid glycoprotein (AGP) have been found to be associated with alpha(1)-acid glycoprotein concentrations in human seminal plasma. The glycosylation pattern of alpha(1)-acid glycoprotein in seminal plasma obtained from men living in infertile couples can undergo alterations in relation ...

Phagocytic cells contain NADPH oxidase that they use for host defense by catalyzing the production of superoxide. Bacterial lipopolysaccharide (LPS) has been found to stimulate NADPH oxidase in mobile and sessile macrophages and microglia. It also evokes fever in homeothermic animals and men, a reaction mediated by central nervous system ...

A simple, efficient and stereospecific approach for the homologation of urethane-protected alpha-amino acids to beta-amino acids by the Arndt-Eistert method employing Fmoc-/Boc-alpha-amino acid and 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyl-uronium hexafluorophosphate mixture for the acylation of diazomethane synthesizing the key intermediates Fmoc-/Boc-alpha-aminodiazomethanes as crystalline solids is described.

Treatment of a vinyl chloride with commercially available aqueous sodium hypochlorite solution in a 2:5 mixture of acetic acid/acetone at 0 degrees C for about 1 h cleanly leads to the corresponding alpha-chloroketone. Similarly, if a vinyl bromide is exposed to sodium hypobromite (freshly prepared from bromine and sodium hydroxide) ...

alpha-Keto amides 10a,b, formed from reaction of pyruvic or benzoylformic acid with allyl amine are found to present as single rotameric forms whilst their tertiary amido analogues 10c, d present as two rotamers in solution at rt. The hydroxyimino derivatives 8 share the conformational characteristics of their parents. The geometrical ...

Deficiency in n-3 fatty acids is known to disturb the release of dopaminergic neurotransmitters in rat brain. Since isomerization reduces the bioavailability of dietary fatty acids, the effect of the conversion of alpha-linolenic acid into trans alpha-linolenic acid on the dopaminergic neurotransmission was studied. Rats were fed for 21 months ...

The bacteriocin, lacticin 3147, increased isoleucine transamination by Lactococcus lactis IFPL359 in a cheese model system. The formation of alpha-keto-beta-methyl-n-valeric acid and 2-hydroxy-3-methyl-valeric acid increased by three times in cheese slurries at 12 degrees C and cheese aroma intensity increased as well, which corresponded with a higher 2-methylbutanal formation.

Protein modification generally occurs by addition to the amino acid side-chains of protein at the post-translational stage, for example, by enzymatic or chemical reactions after polypeptide synthesis. Recently, the recombinant hirudin analog CX-397, a potent thrombin inhibitor, was found to contain methylated Ile residues when it was overproduced by Escherichia ...

Schizophyllan (SPG), a beta-1,3-glucan polysaccharide which is known to form macromolecular complexes with certain polynucleotides, was modified by a reductive amination method with alpha-amino acids (Arg, Lys, and Ser). The thermal stability of the complexes as estimated by T(m) was enhanced in SPG-Arg and SPG-Lys conjugates which have pI values ...

A variety of alpha,alpha-disubstituted malonamides undergo enantioselective hydrolysis with Rhodococcus sp. CGMCC 0497 to give challenging enantiopure alpha,alpha-disubstituted malonamic acids with up to >99% enantiomeric excesses and 98% chemical yields. The enantioselectivity originated from the effects of a highly enantioselective amidase. The products could be converted to valuable (R)- or ...

The photolysis of hop-derived trans-iso-alpha-acids (2a-c; naturally occurring bitter compounds present in beer) and of trans-tetrahydroiso-alpha-acids (5a-c; semi-synthetic advanced hop products) was investigated at 300 nm in methanol. The complex photoreaction mixtures were separated by high-performance liquid chromatography (HPLC) using diode array detection and the major photoreaction products were identified ...

Amino acids seem to have specific preferences for various locations in alpha-helices. These specific preferences, called singlet local propensity (SLP), have been determined by calculating the preference of occurrence of each amino acid in different positions of the alpha-helix. We have studied the occurrence of amino acids, single or pairs, ...

Fused bicyclic alpha-amino acids can be prepared by a double Michael reaction of p-anisyl ethynyl ketone and a tethered diacid, cyclization via hydrogenation or hydration of a CN group, and oxidation of the p-anisyl group. The substitution level of the alpha-amino acids can be adjusted by decyanation or decarboethoxylation of ...

alpha-Fluoroamino acids were targeted in our ongoing efforts to design novel fluoropeptidomimetics (1) as potential protease inhibitors. alpha-Fluoroglycine derivative (2) and alpha-fluoro-beta-aminoethanethiol derivatives (3-9) were synthesized for the first time en route to obtain the peptidomimetic moiety 1. The stability of 2-9 was investigated under organic as well as aqueous ...