Protein Results

Decreased production of yolk protein resulting from inhibition of either ovarian or liver function presents the fish with a similar choice to that resulting from decreased food availability. It can produce the same number of smaller eggs, or a smaller number of eggs of normal size, but the mechanism by which that choice is made is unclear. Since the decreased nutrient content of small eggs will result in smaller larvae with a decreased survival rate, the net result in both cases may be a... 

Cooperativity, the interaction of molecules on a protein resulting from the mutual binding of those molecules. The cooperativity may be positive (whereby the binding of one of the substances facilitates the interaction of the protein with the other molecule) or negative (binding of one molecule decreases the interaction of the protein with the other molecule). 

The reaction scheme of Latia bioluminescence. Based on the structures of luciferin 1 (Ln) and the product of luminescence reaction 2 (OxLn), it was proposed that the luciferase-catalyzed luminescence reaction of Latia luciferin in the presence of the purple protein results in the formation of 2 moles of formic acid, as shown in the scheme A (Shimomura and Johnson, 1968c). However, when the luminescence reaction was carried out in a medium containing ascorbate and NADH (in addition to the purple protein) to increase the quantum yield, it was found that only one mole of formic acid was produced accompanied... 

DMD and BMD DMD and BMD are caused by the absence or deficiency of dystrophin a membrane-associated protein, resulting in increased Ca2+ concentration in muscle, loss of Ca2+ homeostasis, and inappropriate calpain activity36... 

Muscarinic acetylcholine receptors (mAChRs) form a class of cell surface receptors that are activated upon binding of the neurotransmitter, acetylcholine. Structurally and functionally, mAChRs are prototypical members of the superfamily of G protein-coupled receptors. Following acetylcholine binding, the activated mAChRs interact with distinct classes of heterotrimeric G proteins resulting in the activation or inhibition of distinct downstream signaling cascades. 

Originally described in the immune system, NFAT proteins comprise a family of transcriptional factors that play key roles in many cellular processes that control not only immune responses but also the development, regulation, and differentiation of many other tissues. Activation of NFAT proteins results in the expression of specific sets of genes that regulate multiple cell functions [1,2]. 

Small Ubiquitin-like modifier (SUMO) is a conserved protein that is ubiquitously expressed in eukaryotes and is essential for viability. It serves as a reversible posttranslational modifier by forming an isopeptide bond with lysine residues in many target proteins, in a catalytic process termed SUMOylation. SUMOylation of proteins results in altered inter- or intramolecular interactions of the modified target (Fig. 1). 

The frequently used biuret reaction of proteins results in the formation of the following reddish-violet complex in alkaline medium [4, 2S, 26] ... 

Several studies were performed on the optimization of expression levels of ELP proteins in E. coli. In a recent example, the expression protocol was optimized for an ELP fusion with green fluorescent protein (GFP). This fusion protein was expressed and purified in a yield of 1.6 g/L of bacterial culture, which finally yielded 400 mg GFP/L bacterial culture. This extremely high yield was found after uninduced expression in nutrient-rich medium supplemented with phosphate, glycerol and certain amino acids, such as proline and alanine [234]. The influence of fusion order was also examined and it was found that positioning the ELP at the C-terminus of target protein resulted in significantly higher expression levels [35]. 

In a subsequent study, the effect of reducing the ELP molecular weight on the expression and purification of a fusion protein was investigated. Two ELPs, ELP [V-20] and ELP[VsA2G3-90], both with a transition temperature at 40°C in phosphate-buffered saline (PBS) containing 1 M NaCl, were applied for the purification of thioredoxin. Similar yields were observed for both fusion proteins, resulting in a higher thioredoxin yield for the ELP[V-20] fusion, since the ELP fraction was smaller. However, a more complex phase transition behavior was observed for this ELP and therefore a selection of an appropriate combination of salt concentration and solution temperature was required [39]. 

DNA in eukaryotic cells is associated with a variety of proteins, resulting in a strucmre called chromatin. 

Figure 4.14 Diagrammatic representation of (a) oxy-radical>mediated S-thioiation and (b) thiol/disulphide-initiated S-thiolation of protein suiphydryl groups. Under both circumstances mixed disuiphides are formed between glutathione and protein thiois iocated on the ion-translocator protein resulting in an alteration of protein structure and function. Both of these mechanisms are completely reversible by the addition of a suitabie reducing agent, such as reduced glutathione, returning the protein to its native form.

Figure 10 Structure of the target analyte phenoxybenzoic acid (PBA). The arrows point to the ideal sites for conjugation of the molecule to proteins for optimum recognition. Use of site 2 for conjugation to protein resulted in antibodies that recognized free PBA poorly...

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