Bioinorganic Systems

2007 ◽  
Author(s):  
Robert B. Jordan
Keyword(s):  
Spectroscopic Properties ◽  
Biologically Active ◽  
Peptide Sequence ◽  
Prosthetic Group ◽  
Model Complexes ◽  
Active Systems ◽  
Biological Source ◽  
Covalently Bonded ◽  
The Subject ◽  
General Aspects

The field of bioinorganic chemistry has grown tremendously in the past 25 years. Much of the work is concerned with establishing the coordination site, ligand geometry and metal oxidation state in biologically active systems. The field also extends to the preparation and characterization of simpler model complexes that mimic the spectroscopic properties and perhaps some of the reactivity of the biological system. Much of this characterization work must precede meaningful mechanistic studies. Williams has provided an interesting overview of metal ions in biology from an inorganic perspective. There are several early review series and specialized journals devoted to the subject, and a recent issue of Chemical Reviews is devoted to the area. There also are several books covering general aspects of the subject. The field is so large and the systems are so individualistic that it is necessary, for the purposes of a text such as this, to choose a few sample systems as illustrative of the mechanistic achievements and problems. Studies of bioinorganic systems inevitably use some terminology from biochemistry which may be unfamiliar to an inorganic chemist. The examples in this Chapter are all metalloenzymes which catalyze some process. Clearly they contain a metal, but there are other components of an enzyme, and terms used to describe these are summarized as follows: An apoenzyme is a polypeptide whose composition, peptide sequence and structure depend on the biological source of the metalloenzyme. Typically, the molar mass of the polypeptide is in the range of 1.5-5xl05 daltons. The polypeptide is folded into coils and sheets whose shape is determined by electrostatics and hydrogen bonding. These terms designate the same type of component, but one or the other is used more commonly for a particular system. This is a nonprotein component which binds to the apoenzyme to produce the active catalyst. It is not covalently bonded to the apoenzyme and can be removed by relatively mild denaturation of the polypeptide. Common bioinorganic examples are coenzyme B12, discussed in Section 8.3, and Zn(II) in carbonic anhydrase, discussed in Section 8.4. A prosthetic group is analogous to a coenzyme except that a prosthetic group is believed to be covalently bonded to the apoenzyme.

Introductory remarks

1981 ◽  
Vol 302 (1468) ◽  
pp. 219-219
Keyword(s):  
State Of The Art ◽  
Biological Processes ◽  
Industrial Workers ◽  
Practical Application ◽  
Electroanalytical Methods ◽  
Secondary Battery ◽  
On Line ◽  
The Subject ◽  
General Aspects ◽  
Cross Fertilization

As its title suggests, the purpose of this Discussion Meeting is to review the present state of the art in industrial electrochemistry. We have sought to bring together academic and industrial workers in this field as well as other interested participants. I hope that as the meeting proceeds, a cross-fertilization of ideas will occur both in the formal sessions and during the breaks. The organizers of this Meeting have given considerable thought to the order in which the different aspects of electrochemistry should be presented. Evidently we had to begin with the fundamentals, after which we decided to deal with the general aspects of electrosynthesis including the developing possibilities of supplying energy to biological processes by electrochem ical means. This led naturally to consideration of electrochemical engineering and electroanalytical methods for on-line control. In one session we shall move to a very practical application of electrochemistry, namely batteries. Beginning with Volta’s simple cell, this application is one of the oldest in electrochemistry. In spite of all the advances in the subject, the possibilities of new primary and secondary battery systems remain as wide as ever. I, for one, shall be most interested to hear the progress reports of our three speakers.

Prototype Testing of Aircraft

1950 ◽  
Vol 54 (474) ◽  
pp. 359-370
Author(s):  
D. R. H. Dickinson
Keyword(s):  
Short Paper ◽  
Wide Field ◽  
Flight Tests ◽  
The Subject ◽  
General Aspects ◽  
Small Aircraft ◽  
Prototype Testing

The title of Prototype Testing is taken here to refer to the flight tests carried out on a new aircraft by its constructor. It embraces a wide field of subjects and in a short paper, it cannot be covered in any way comprehensively. I propose therefore to deal mainly with very general aspects of the subject.The paper does not attempt to embrace out of the ordinary types with special problems peculiar to themselves—an extreme example of which is probably the Brabazon I. Most of my experience on this subject has been concerned with small aircraft, many of them single-seaters, and consequently some of my statements may apply more particularly to this type of aircraft, although many will probably apply equally to other types of aircraft.

Studies on Enaminoketones

1974 ◽  
Vol 52 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Ivo Jirkovsky
Keyword(s):  
Cyanogen Bromide ◽  
Spectroscopic Properties ◽  
Phenyl Isocyanate ◽  
Biologically Active ◽  
Side Chain ◽  
Phenyl Isothiocyanate ◽  
Methyl Isothiocyanate ◽  
Synthetic Utility ◽  
Concentrated Sulfuric Acid ◽  
Biologically Active Derivatives

A series of N-substituted 3-amino-2-cyclohexen-1-ones and 3-amino-5,5-dimethyl-2-cyclohexen-1-ones (1–9) has been prepared. Halogenation of these compounds with bromine, NBS, cyanogen bromide, and iodine is described. The tendency of enaminoketones to form salts of the corresponding enol-ketimine form was observed and structures of the salts are supported by their p.m.r. and i.r. properties. The reaction of 3-benzylamino-2-bromo-5,5-dimethyl-2-cyclohexen-1-one with concentrated sulfuric acid effected debenzylation. Treatment of 3-benzylamino-2-iodo-5,5-dimethyl-2-cyclohexen-1-one with dibenzoyl peroxide gave 8,8a-dihydro-5-iodo-8,8-dimethyl-2,3-diphenyl-4H-1,4-benzoxazine-6,7-diol. The above secondary enaminoketones 1–9 were shown to react with phenyl isocyanates, phenyl isothiocyanate. and methyl isothiocyanate under fusion conditions to yield substituted 2-amino-6-oxo-1-cyclo-hexene-1-carboxamides and corresponding thiocarboxamides. 2-Benzylamino-6-oxo-N-phenyl-1-cyclohexene-1-carboxamide and its 5,5-dimethyl analog were found to undergo facile transamination in position 2, when heated with a primary amine. This reaction is of synthetic utility for the preparation of biologically active derivatives with a basically substituted side chain. Addition of 4-methylamino-3-pentene-2-one to phenyl isocyanate afforded 2-acetyl-3-methylaminoisocrotonanilide; the spectroscopic properties of this product are discussed.

Synthesis and Characterization of Chiral Conducting Polymers Based on Polypyrrole

1997 ◽  
Vol 50 (9) ◽  
pp. 939 ◽  
Author(s):  
Fang Chen ◽  
Parveen Akhtar ◽  
Leon A. P. Kane-Maguire ◽  
Gordon G. Wallace
Keyword(s):  
Conducting Polymers ◽  
Propionic Acid ◽  
Spectroscopic Properties ◽  
Optically Active ◽  
Synthesis And Characterization ◽  
Chiroptical Properties ◽  
Covalently Bonded ◽  
Circular Dichroïsm ◽  
Ring Position

A range of optically active pyrrole monomers have been synthesized in which a chiral sub- stituent is covalently bonded either to the pyrrole N or C3 ring position, namely (–)-(1R)-4-methyl-N-(1-phenylethyl)pyrrole-3-carboxamide, (+)-(1S)-4-methyl-N-(1-phenylethyl)pyrrole-3-carboxamide, (–)-(1R)-4-methyl-N-(1-naphthylethyl)pyrrole-3-carboxamide, (+)-(1S)-4-methyl-N-(1-naphthylethyl)pyrrole-3-carboxamide, (+)-(2S)-2-(1H-pyrrol-1-yl)propionic acid, (+)-(1S)-N-(1-phenyl-ethyl)pyrrole, and (–)-(1R)-N-(1-phenylethyl)pyrrole. Their chiroptical properties have been established by circular dichroism spectroscopy. Electropolymerization of the three N-substituted pyrrole monomers provided films of chiral conducting polymers, whose electrical and spectroscopic properties are described. Although oxidation of the C3 substituted pyrrole monomers was also facile, electrodeposition was poor and films of the associated polymers could not be obtained.

The Mechanical Requirements of the Royal National Lifeboat Institution

1941 ◽  
Vol 145 (1) ◽  
pp. 30-37 ◽  
Author(s):  
P. H. Johnson
Keyword(s):  
Rolling Resistance ◽  
Not Given ◽  
Internal Corrosion ◽  
The Past ◽  
Alternative Method ◽  
The Subject ◽  
Special Mention ◽  
General Aspects ◽  
The Relationship

After dealing briefly with the historical and general aspects of the subject, the author touches on the disposition of lifeboats round the coast and the factors which govern this distribution. Details of the boats themselves and their equipment are not given, but the paper concentrates on the difficulties involved, and the methods and equipment employed, in launching from the beach. Certain difficult beach conditions have been met by mounting the 11 tons of lifeboat and carriage on track units of the rigid girder type. Reference is made to the wheels employed in launching lighter boats in the past. Excessive rolling resistance made these wheels impracticable for soft beaches. The relationship between rolling resistance and the width and diameter of steel-tyred wheels is given, together with a description of the girdled wheels devised some forty years ago by Commander Gartside-Tipping, R.N. The development and construction of the girder track units now employed in place of wheels is fully dealt with. The method of launching a lifeboat by tractor is described, and shows how necessary are extreme reliability and watertightness in the tractor employed. The lifeboat “roadless” tractor is then described in detail and particulars given of the methods by which it is made waterproof. Special mention is made of gear for extracting the tractor from quicksand or mud pockets, and a résumé is given of the experience gained in this direction with tanks during the war of 1914–18. An alternative method to that adopted for waterproofing the tractor is referred to. A summary is provided of the submergence and other tests to which the tractor is subjected and of the special precautions which are taken in service to prevent trouble arising from internal corrosion due to condensation. The paper closes with the possible applications in other directions of the experience gained with the machinery described.

Mössbauer spectroscopy: epoch-making biological and chemical applications

2017 ◽  
Vol 89 (4) ◽  
pp. 461-470
Author(s):  
Adriana Lancok ◽  
Lenka Volfova
Keyword(s):  
Inorganic Chemistry ◽  
Mössbauer Spectrometry ◽  
Biologically Active ◽  
Trivalent Iron ◽  
Methyl Groups ◽  
Biological Applications ◽  
Sandwich Complexes ◽  
Iron Compounds ◽  
Active Systems ◽  
Mossbauer Spectrometry

AbstractIron is one of the most abundant elements on Earth and also in Mössbauer research. The present study is a summary of our search for iron compounds that now play an important role in the development of specific areas of inorganic chemistry of iron, biological applications and pigment for various types of artworks. The different catalytic or biologically active systems were studied in particular of the Mössbauer spectrometry, including temperature dependencies of the biological tissue and the synthetic vivianite. Mössbauer spectrometry was chosen as the main investigation tool for identification of Fe2+ and Fe3+. We are identified divalent and trivalent iron in the samples and we found their mutual ratio. The iron sandwich complexes exhibit a linear dependence between quadrupole splitting and number of methyl groups. We also determined temperature of transformation of divalent to trivalent iron for vivianite sample that are used in painting. The transformation temperature is about 90°C.

P1-118: SYNTHESES OF BIOLOGICALLY ACTIVE AND COVALENTLY BONDED AMYLOID-B DIMERS

2014 ◽  
Vol 10 ◽  
pp. P344-P344
Author(s):  
Sejin Lee ◽  
Hye Yun Kim ◽  
Youngsoo Kim
Keyword(s):  
Biologically Active ◽  
Covalently Bonded

scholarly journals Dissociation of catalase. A correlation between changes in sedimentation and spectroscopic properties accompanying dissociation of bacterial catalase in alkaline solution

1970 ◽  
Vol 118 (2) ◽  
pp. 319-323 ◽  
Author(s):  
Peter Jones ◽  
R. H. Pain ◽  
A. Suggett
Keyword(s):  
Sedimentation Coefficient ◽  
Spectroscopic Properties ◽  
Sedimentation Equilibrium ◽  
Prosthetic Group ◽  
Environmental Constraint ◽  
Degree Of Dissociation ◽  
Slow Moving ◽  
High Concentrations ◽  
Soret Absorption ◽  
Soret Region

1. At high concentrations, in 10mm-phosphate buffer, pH7.0, the sedimentation coefficient of bacterial catalase varies with concentration according to: [Formula: see text] with S020,w=11.30S and ks=6.29×10−3ml mg−1. Sedimentation-equilibrium experiments yield a molecular weight of 240000. 2. Parallel studies of changes in sedimentation-velocity behaviour and in electronic spectra of bacterial catalase at pH>11 were made. Dissociation is indicated by the appearance of a slow-moving (2.9S) component in sedimentation patterns and this is accompanied by marked changes in absorption spectrum in the Soret region. Values of R=E406/E355 show a theoretically predictable near-linear dependence on α, the degree of dissociation calculated from ultracentrifuge data. 3. The Soret absorption of bacterial catalase subunits is much lower than that of the native enzyme, and it is suggested that dissociation produces an environmental constraint on the prosthetic group that results in distortion of the porphyrin ring.

Zn(ii) and Cu(ii) complexes containing bioactive O,O-chelated ligands: homoleptic and heteroleptic metal-based biomolecules

2015 ◽  
Vol 44 (20) ◽  
pp. 9321-9334 ◽  
Author(s):  
Barbara Sanz Mendiguchia ◽  
Iolinda Aiello ◽  
Alessandra Crispini
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Spectroscopic Properties ◽  
Delivery Systems ◽  
Biologically Active ◽  
Donor Ligands ◽  
Diagnostic Agents

Zn(ii) or Cu(ii) highly stable complexes with chelated O,O-donor ligands from natural extractions give rise to drug delivery systems, new biologically active complexes and potential diagnostic agents due to their intrinsic spectroscopic properties.

scholarly journals Enzymatic Synthesis and Functional Characterization of Bioactive Microcin C-Like Compounds with Altered Peptide Sequence and Length

2015 ◽  
Vol 197 (19) ◽  
pp. 3133-3141 ◽  
Author(s):  
Olga Bantysh ◽  
Marina Serebryakova ◽  
Inna Zukher ◽  
Alexey Kulikovsky ◽  
Darya Tsibulskaya ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biological Activity ◽  
Functional Characterization ◽  
Trna Synthetase ◽  
Biologically Active ◽  
Peptide Sequence ◽  
Target Cells ◽  
Content Type ◽  
Peptide Length

ABSTRACTEscherichia colimicrocin C (McC) consists of a ribosomally synthesized heptapeptide attached to a modified adenosine. McC is actively taken up by sensitiveEscherichia colistrains through the YejABEF transporter. Inside the cell, McC is processed by aminopeptidases, which release nonhydrolyzable aminoacyl adenylate, an inhibitor of aspartyl-tRNA synthetase. McC is synthesized by the MccB enzyme, which terminally adenylates the MccA heptapeptide precursor MRTGNAN. Earlier, McC analogs with shortened peptide lengths were prepared by total chemical synthesis and were shown to have strongly reduced biological activity due to decreased uptake. Variants with longer peptides were difficult to synthesize, however. Here, we used recombinant MccB to prepare and characterize McC-like molecules with altered peptide moieties, including extended peptide lengths. We find that N-terminal extensions ofE. coliMccA heptapeptide do not affect MccB-catalyzed adenylation and that some extended-peptide-length McC analogs show improved biological activity. When the peptide length reaches 20 amino acids, both YejABEF and SbmA can perform facilitated transport of toxic peptide adenylates inside the cell. A C-terminal fusion of the carrier maltose-binding protein (MBP) with the MccA peptide is also recognized by MccBin vivoandin vitro, allowing highly specific adenylation and/or radioactive labeling of cellular proteins.IMPORTANCEEnzymatic adenylation of chemically synthesized peptides allowed us to generate biologically active derivatives of the peptide-nucleotide antibiotic microcin C with improved bioactivity and altered entry routes into target cells, opening the way for development of various McC-based antibacterial compounds not found in nature.

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