Alisol C Monoacetate/(8α,9β,11β,14β,24R)-11-Hydroxy-3,16-dioxo-24,25-epoxydammar-13(17)-en-23-yl acetate/ALISOL C ACETATE/Alisol Cmonoacetate/AlisolCmonoacetate/Alisol C-23-acetate/Dammar-13(17)-ene-3,16-dione, 23-(acetyloxy)-24,25-epoxy-11-hydroxy-, (8α,9β,11β,14β,24R)-/23-Acetyl alisol C/23-Acetyl-alisol-C/Alisol C (23-acetate)
Soluble in Chloroform,Dichloromethane,Ethyl Acetate,DMSO,Acetone,etc.
624.9±55.0 °C at 760 mmHg
HS Code Reference
Personal Projective Equipment
For Reference Standard and R&D, Not for Human Use Directly.
provides coniferyl ferulate(CAS#:26575-93-9) MSDS, density, melting point, boiling point, structure, formula, molecular weight etc. Articles of coniferyl ferulate are included as well.>> amp version: coniferyl ferulate
A large number of structural determinations of compounds containing 2-hydroxy-3,5-dinitrobenzoic acid (I) and its various deprotonated forms, 2-hydroxy-3,5-dinitrobenzoate (II) or 2-carboxy-4,6-dinitrophenolate (III), are biased. The reason for the bias follows from incorrectly applied constraints or restraints on the bridging hydrogen, which is involved in the intramolecular hydrogen bond between the neighbouring carboxylic/carboxylate and oxo/hydroxy groups. This hydrogen bond belongs to the category of resonance-assisted hydrogen bonds. The present article suggests corrections for the following structure determinations that have been published in Acta Crystallographica: DUJZAK, JEVNAA, LUDFUL, NUQVEB, QIQJAD, SAFGUD, SEDKET, TIYZIM, TUJPEV, VABZIJ, WADXOR, YAXPOE [refcodes are taken from the Cambridge Structural Database [CSD; Groom et al. (2016 ?). Acta Cryst. B72, 171-179]. The structural features of the title molecules in all the retrieved structures, together with structures that contain 3,5-dinitro-2-oxidobenzoate (IV), are discussed. Attention is paid to the localization of the above-mentioned bridging hydrogen, which can be situated closer to the O atom of the carboxylate/carboxylic group or that of the hydroxy/oxo group. In some cases, it is disordered between the two O atoms. The position of the bridging hydrogen seems to be dependent on the pK a(base) although with exceptions. A stronger basicity enhances the probability of the presence of a phenolate (III). The present article examines the problem of the refinement of such a bridging hydrogen as well as that of the hydrogen atoms involved in the hydroxy and primary and secondary amine groups. It appears that the best model, in many cases, is obtained by fixing the hydrogen-atom position found in the difference electron-density map while refining its isotropic displacement parameter.
crystal structure, resonance-assisted hydrogen bonds, refinement constraints, 2-hydroxy-3,5-dinitrobenzoic acid, 2-hydroxy-3,5-dinitrobenzoate, 2-carboxy-4,6-dinitrophenolate, 3,5-dinitro-2-oxidobenzoate
A resonance-assisted intramolecular hydrogen bond in compounds containing 2-hydroxy-3,5-dinitrobenzoic acid and its various deprotonated forms: redetermination of several related structures
2018 Sep 1
The terminal deoxynucleotidyltransferase (TdT) gene encodes a template-independent DNA polymerase that is expressed exclusively in immature lymphocytes. The TdT promoter lacks a TATA box, but an initiator element (Inr) overlaps the transcription start site. The Inr directs basal transcription and also mediates activated transcription in conjunction with an upstream element called D’. We have begun to address the fundamental question of why the TdT promoter contains an Inr rather than a TATA box. First, we tested the possibility that the TdT promoter lacks a TATA box because the -30 region is needed for the binding of an essential regulator. Mutations were introduced into the -30 region, and the mutants were tested in transient transfection and in vitro transcription assays. The mutations had only minor effects on promoter strength, suggesting that this first hypothesis is incorrect. Next, the effect of inserting a TATA box within the -30 region was tested. Although the TATA box enhanced promoter strength, appropriate regulation appeared to be maintained, as transcription in lymphocytes remained dependent on the D’ element. Finally, a promoter variant containing a TATA box at -30, but a mutant Inr, was tested. Surprisingly, transcription from this variant, both in vitro and in vivo, was dramatically reduced. These results suggest that the TdT promoter, and possibly other natural promoters, contain an Inr element because one or more activator proteins that interact with surrounding control elements preferentially function in its presence.
Transcription of the lymphocyte-specific terminal deoxynucleotidyltransferase gene requires a specific core promoter structure.
I P Garraway, K Semple, and S T Smale
1996 Apr 30;
Voltage-gated proton channels (HV) are unique, in part because the ion they conduct is unique. HV channels are perfectly selective for protons and have a very small unitary conductance, both arguably manifestations of the extremely low H+ concentration in physiological solutions. They open with membrane depolarization, but their voltage dependence is strongly regulated by the pH gradient across the membrane (ΔpH), with the result that in most species they normally conduct only outward current. The HV channel protein is strikingly similar to the voltage-sensing domain (VSD, the first four membrane-spanning segments) of voltage-gated K+ and Na+ channels. In higher species, HV channels exist as dimers in which each protomer has its own conduction pathway, yet gating is cooperative. HV channels are phylogenetically diverse, distributed from humans to unicellular marine life, and perhaps even plants. Correspondingly, HV functions vary widely as well, from promoting calcification in coccolithophores and triggering bioluminescent flashes in dinoflagellates to facilitating killing bacteria, airway pH regulation, basophil histamine release, sperm maturation, and B lymphocyte responses in humans. Recent evidence that hHV1 may exacerbate breast cancer metastasis and cerebral damage from ischemic stroke highlights the rapidly expanding recognition of the clinical importance of hHV1.
Voltage-Gated Proton Channels: Molecular Biology, Physiology, and Pathophysiology of the HV Family
Thomas E. DeCourseycorresponding author