Fc Derivatives Research Articles

Designer Peptides: Attempt to Control Peptide Structure by Exploiting Ferrocene as a Scaffold

AbstractThe design of peptides that display a β‐sheet‐like secondary structure remains a challenge. Molecular scaffolds, such as ferrocene (Fc) can help to overcome some of these challenges. Monosubstituted Fc derivatives offer no control over the self‐assembly of the conjugates, and the formation of supramolecular structures is entirely serendipitous. 1,n′‐disubstituted Fc derivatives provide a significant level of control over the direction of the peptide, their relative orientation, and the intramolecular hydrogen‐bonding patterns, which increases the rigidity of the molecule and in many cases, generates a new H‐bonding interface for intermolecular assembly. In this Microreview, we explore the use of ferrocene as a scaffold in the design of structurally well‐defined peptide conjugates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Ferrocene-Nafion Modified Electrode And Its Catalysis For Cerium (IV)

Abstract Ferrocene-Nafion modified electrode is prepared, it exhibits an interesting electrocatalysis for Ce(IV) reaction. Many investigations have been done on ferrocene (Fc) derivative and polymer modified electrodes,1–6 but seldom reported the modified electrodes simply with Fc containing no substituents. Because in the latter case it was very difficult to attach the modifier to the electrode surface by conventional methods such as plasma polymerization,1 electrodeposit,2 electropolymerization,3 covalence link,4 ion exchange5 and polymer coating6 etc. Nafion modified electrodes7–10 have attracted much interest for its ion exchange property. Considering Nafion possesses another property-hydrophobic interaction, here we propose a noval modified electrode with complex Fc by the help of Nafion. The Fc-Nafion modified electrode prepared shows well defined cyclic voltammogram of Fc. It has more stable and reversible voltammetric characteristics compared with other Fc derivative electrodes. What interesting c...

Selective killing of human T cell lymphotropic virus type I-transformed cell lines by a damavaricin Fc derivative.

n-Pentyl ether of damavaricin Fc (n-pentyl DvFc) preferentially killed human T-cell lymphotropic virus type I (HTLV-I)-transformed cell lines. The mechanism of action of the drug was investigated using MT-4 cells. Cytotoxic action was diminished by the removal of n-pentyl DvFc from the culture or by the addition of sulfhydryl compounds such as 2-mercaptoethanol and dithiothreitol. The killing activity of n-pentyl DvFc was also diminished by membrane-acting agents including quinidine and diphenylhydantoin. Influx and subsequent efflux of Ca2+ were observed when either HTLV-I infected (MT-4 cells) or uninfected cells were treated with n-pentyl DvFc. An efflux of K+ was observed in HTLV-I infected MT-4 cells immediately after the exposure of the cells to n-pentyl DvFc. The K+ efflux, however, was not observed in the uninfected T cells. n-Pentyl DvFc seems to act primarily on the cell surface of MT-4 cells, leading to the perturbation of membrane function. The restoration of cell growth, however, is critically dependent on the presence of dithiothreitol and 2-mercaptoethanol, implying a role for a free sulfhydryl group in the killing activity.

Iron-containing metallocenes as active site directed inhibitors of the proteinase that cleaves the NH2-terminal propeptides from type I procollagen.

Derivatives of ferrocene (dicyclopentadienyliron) (Fc) were examined as active site directed inhibitors of type I procollagen N-proteinase, the enzyme that cleaves the NH2-terminal propeptides from type I procollagen. The compounds were shown here to be reversible, competitive inhibitors of the enzyme. The effectiveness of the Fc inhibitors varied with modification of the cyclopentadienyl (cp) rings. The monocarboxylic acid (I) and the 1,1'-dicarboxylic acid (II) derivatives of Fc inhibited 50% of the enzymic activity (I50) at concentrations of 1.0 and 0.5 mM, respectively. The Ki values were 0.3 mM for both I and II. Derivatization of the carbonyl alpha to the cp ring of compound I (FcCOCH2CH2COOH, III) increased the inhibitory activity (I50 = 0.100 mM; Ki = 0.065 mM). Removal of the carbonyl alpha to the cp ring of III did not improve inhibitory activity: FcCH2CH2COOH, I50 = 2 mM; FcCH = CHCOOH, I50 = 1.5 mM. The active inhibitory species apparently contained iron in the 3+ valence state since two ferrocenium derivatives were very effective inhibitors: ferrocenium tetrachloroferrate, IV (I50 = 0.030 mM; Ki = 0.004 mM), and carboxyferrocenium hexafluorophosphate, V (I50 less than 0.1 mM; Ki less than 0.05 mM). In addition, reduction of III with ascorbic acid abolished its inhibitory activity. Compounds I and III stabilized the enzyme to heat denaturation in the absence of exogenous calcium; compound IV did not stabilize the enzyme. Further observations indicated that Fc derivatives were specific inhibitors of procollagen N-proteinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of focus formation of rat cells by mouse sarcoma virus by damavaricin Fc derivatives.

Inhibition of focus formation of rat cells by mouse sarcoma virus by damavaricin Fc derivatives.