A reagent and a derivatization procedure have been developed which result in trimesylation of all -OH and -NH2 groups on proteins: serine, threonine, tyrosine, and lysine side chains are all completely derivatized. The parameters affecting the kinetics of trimesylation of serine, threonine, and tyrosine peptides were studied using dinitrophenylated peptides as model systems. Conditions for solu...

11 -eis Retinal ((1) see Fig. 1) and its 3,4-dehydro derivative (11-ds A2-retinal, (2)) were believed to be the sole chromophores in the visual pigments. Recently, another retinal compound — 3-hydroxy retinal (3) — was identified as the functional chromophore in the eyes of several related insect orders [1—3]. It was demonstrated that the adaptation of 3-hydroxy retinal as visual chromophore pr...

The aim of these notes is to illustrate a proof of the following remarkable Theorem of Alberti (first proved in [1]). Here, when μ is a Radon measure on Ω ⊂ R, we denote by μ its absolutely continuous part (with respect to the Lebesgue measure L ), by μ := μ− μ its singular part, and by |μ| its total variation measure. Clearly, |μ|a = |μa| and |μ|s = μ. When μ = Du for some u ∈ BV (Ω,R), we wil...

Earlier we reported the tendency of ferrocenylmethyl substituted amino acids to organize around Cu(ii) in a C(2) symmetry. In this paper we have utilized this property to form a chiral cavity using a l-tyrosine derivative. Structural characterization of [Cu(II)(S-fTyr)(2)(MeCN)(2)] (), where S-fTyr(1-) is ferrocenylmethyl-l-tyrosinate, showed that the alignment of two tyrosine aromatic rings ar...

A universal approach by Laplace transform to the variational iteration method for fractional derivatives with the nonsingular kernel is presented; in particular, the Caputo-Fabrizio fractional derivative and the Atangana-Baleanu fractional derivative with the non-singular kernel is considered. The analysis elaborated for both non-singular kernel derivatives is shown the necessity of considering...

Methyl 3-O-p-methoxybenzyl-beta-D-xylopyranoside (2) was exploited as a novel hinge-type tether for the [2 + 2] cycloaddition of cinnamate. The major ring conformation occupied by the 2,4-dicinnamate derivative of 2 was 4C1, which extends two cinnamates along a diequatorial orientation. However, 3-O-deprotected dicinnamate 5, when in a non-polar solvent, favours the 1C4 conformation, which assi...

Dihydrotachysterol and 5,6-trans-cholecalciferol are biologically active analogues of cholecalciferol (vitamin D) with a similarity in steric structure to 1,25-dihydroxycholecalciferol, the active form of the vitamin. The question arises as to the nature of the active form of these analogues. High specific radioactivity (14)C- and (3)H-labelled forms of dihydrotachysterol and 5,6-trans-cholecal...

Sialic acids are involved in a plethora of important biological events; among these the most known certainly is the binding of N-acetylneuraminic acid (Neu5Ac) with influenza virus sialidase. Considering Neu5Ac as the template that led to the structure-based development of the two potent antiviral agents zanamivir and oseltamivir, we developed the synthesis of the sialylexoenitol, a new class o...

A new simple phloroglucinol derivative characterized as 1-(6-hydroxy-2,4-dimethoxyphenyl)-2-methyl-1-propanone (1) was isolated from Hypericum cistifolium (Hypericaceae) as a major constituent of the non-polar plant extract. Minor amounts of this new compound, in addition to two known structurally related phloroglucinol derivatives (2 and 3), and two new terpenoid derivatives characterized, res...

Strain AX-2T (T = type strain) was isolated from sediment of Great Salt Lake, Utah, USA. Optimal salinity for growth was 27% (w/v) NaCl and only a few carbohydrates supported growth of the strain. Strain AX-2T did not grow on complex substrates such as yeast extract or peptone. 16S rRNA analysis revealed that strain AX-2T was a member of the phyletic group defined by the family Halobacteriaceae...