Search results for "affinity"

The critical concentration of C1-esterase inhibitor (C1-INH) in human serum preventing auto-activation of the first component of complement (C1)

2005

C1-esterase inhibitor (C1-INH) was depleted from normal human serum (NHS) at 4 degrees C by affinity chromatography with a monoclonal anti-C1-INH antibody (mAb 13 E1) coupled to CNBr-activated Sepharose 4B. The C1-INH-depleted serum (C1-INH-depl-HS) had normal levels of C1, C4, and CH 50 and C1-INH concentration was less than 10% of normal (15 microg/ml in C1-INH-depl-HS compared to 230 microg/ml in NHS). C1-auto-activation in C1-INH-depl-HS was followed by measuring C4-consumption in a haemolytic assay and by detection of activated C1s in a C1s-ELISA. After a lag phase of 10-20 min, C1-auto-activation in C1-INH depl-HS occurred and reached its maximum after 40 min at 37 degrees C. In contr…

Datamining: Pemanfaatan Algoritma Apriori dalam Menganalisa Pola-Pola Transaksi yang Terjadi

2012

This paper will be described about implementation and analysis of the well-known apriori algorithm, which is called Market Basket Analysis (MBA) in data mining. This algorithm is widely used to predict the relation among market basket in the huge amount of database. This algorithm is based on the concept of a prefix tree. There are several ways to organize the nodes of such a tree, to encode the items, and to organize the transactions, which may be used in order to minimize the time needed to find the frequent itemsets as well as to reduce the amount of memory needed to store the counters. The rules produced will be used by management of supermarket to organize the items set to increase the…

ATTIVITÀ RNA LEGANTE DELLA PROTEINA CSD-C2 RICOMBINANTE PRODOTTA IN ESCHERICHIA COLI RNA BINDING ACTIVITY OF RECOMBINANT CSD-C2 PROTEIN EXPRESSED IN …

2010

Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli

2004

Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin–agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7 free biotin-binding sites per tetramer and showed the same biotin-binding affinity and thermal stability as egg-white avidin. Avidin crystallized under various conditions, which will enable X-ray cryst…

Guest-to-host proton transfer in melatonin-beta-cyclodextrin inclusion complex by ionspray, fast atom bombardment and tandem mass spectrometry.

2001

Ionspray (IS) and fast atom bombardment (FAB) positive ionization mass spectrometry (MS) of 1:1 β-cyclodextrin (β-CD)-melatonin (MLT) host-guest complex allowed the detection of gaseous protonated 1:1 β-CD-MLT. Tandem MS collision-induced dissociation (CID) of such protonated 1:1 β-CD-MLT species showed the proton (charge) to be retained to a significant extent by the host and by its cage fragmentation products, in spite of the higher proton affinity of MLT with respect to that of β-CD. This requires an endothermic guest-to-host proton transfer to occur within the gaseous association. Collisional activation could be accounted for by the promotion of such an endothermic process; however…

Nitration of cathepsin D enhances its proteolytic activity during mammary gland remodelling after lactation

2009

Proteomic studies in the mammary gland of control lactating and weaned rats have shown that there is an increased pattern of nitrated proteins during weaning when compared with controls. Here we report the novel finding that cathepsin D is nitrated during weaning. The expression and protein levels of this enzyme are increased after 8 h of litter removal and this up-regulation declines 5 days after weaning. However, there is a marked delay in cathepsin D activity since it does not increase until 2 days post-weaning and remains high thereafter. In order to find out whether nitration of cathepsin D regulates its activity, iNOS (inducible nitric oxide synthase)−/− mice were used. The expression…

Detection of Single Oxygen Molecules with Fluorescence-Labeled Hemocyanins

2005

This study introduces a method to detect individual oxygen molecules by fluorescence microscopy of single hemocyanins. These respiratory proteins from a tarantula bind oxygen with high affinity. A spectrometric signature of the oxygenated protein is transferred to an attached fluorescence label, which can be detected at the single-molecule level. This technique opens new perspectives for the development of small and sensitive oxygen sensors as well as for the investigation of cooperative oxygen binding in respiratory proteins.

Lanthanide Discrimination with Hydroxyl-Decorated Flexible Metal–Organic Frameworks

2018

We report two new highly crystalline metal-organic frameworks (MOFs), derived from the natural amino acids serine (1) and threonine (2), featuring hexagonal channels densely decorated with hydroxyl groups belonging to the amino acid residues. Both 1 and 2 are capable of discriminating, via solid-phase extraction, a mixture of selected chloride salts of lanthanides on the basis of their size, chemical affinity, and/or the flexibility of the network. In addition, this discrimination follows a completely different trend for 1 and 2 because of the different locations of the hydroxyl groups in each compound, which is evocative of steric complementarity between the substrate and receptor. Last bu…

Production of Hev b5 as a fluorescent biotin-binding tripartite fusion protein in insect cells

2005

The presented green fluorescent protein and streptavidin core-based tripartite fusion system provides a simple and efficient way for the production of proteins fused to it in insect cells. This fusion protein forms a unique tag, which serves as a multipurpose device enabling easy optimization of production, one-step purification via streptavidin-biotin interaction, and visualization of the fusion protein during downstream processing and in applications. In the present study, we demonstrate the successful production, purification, and detection of a natural rubber latex allergen Hev b5 with this system. We also describe the production of another NRL allergen with the system, Hev b1, which fo…

Recombinant avidin and avidin-fusion proteins.

2000

Both chicken egg-white avidin and its bacterial relative streptavidin are well known for their extraordinary high affinity with biotin (Kd approximately 10(-15) M). They are widely used as tools in a number of affinity-based separations, in diagnostic assays and in a variety of other applications. These methods have collectively become known as (strept)avidin-biotin technology. Biotin can easily and effectively be attached to different molecules, termed binders and probes, without destroying their biological activity. The exceptional stability of the avidin-biotin complex and the wide range of commercially available reagents explain the popularity of this system. In order by genetic enginee…