Protein limitation

Chan LM, Lowes S, Hirst BH (2004) The ABCs of drug transport in intestine and liver efflux proteins limiting drug absorption and bioavailability. Eur J Pharm Sci 21 25—51... 

Protein stress has been proposed to cause tissue nitrogen isotope emich-ment (Hare et al. 1991 Hobson and Clark 1992). Diets B and C, with 5% protein by weight, produced offspring that achieved substantially smaller adult weights, clearly demonstrating protein limitation. In many cases the... 

How might cellular growth drive Gl/S transitions A mechanism in which an unstable, translationally regulated protein limits Gl/S transitions provides one possible explanation. Consistent with this, we found that ectopic Rasvl2 or d-Myc increased levels of cyclin E, and that this effect was post-transcriptional (Prober ... 

When such investigation is technically possible, as shown in the examples of MAbs and CD40L, MS analysis of complete molecules is fast, powerful, and the method of choice to obtain detailed characterization information. Such a technique should be among the first to be applied for the study of a therapeutic protein. Limitations of the technique include lack of resolution of heterogeneous mixtures and lack of interpretation of isobaric structures, identical in mass but molecularly distinct. The first point can be overcome by reduction of heterogeneity... 

Bone proteins Limits crystal growth (Gla proteins)... 

Steinert, P. M., Chou, Y.-H., Prahlad, V., Parry, D. A. D., Marekov, L. N., Wu, K. C., Jang, S.-I., and Goldman, R. D. (1999b). A high molecular weight intermediate filament-associated protein in BHK-21 cells is nestin, a Type VI intermediate filament protein Limited co-assembly in vitro to form heteropolymers with Type III vimen-tin and Type IV a-Internexin./ Biol. Chem. 274, 9881-9890. 

In other studies on the domain structure of oligomeric proteins, limited proteolysis, deletions, and site-directed mutagenesis have also successfully provided information about subunit contact regions. Functional domains containing subunit interaction sites of cAMP-dependent protein kinase22 and carbamoyl phosphate synthetase23 have been revealed by such experiments. 

Many proteins, and notably albumin, contain weak acidic and basic groups within their structure. Therefore, plasma and other proteins form important buffering systems. Intracellular proteins limit pH changes within cells, whilst the protein matrix of bone can buffer large amounts of hydrogen ions in patients with chronic acidosis. 

In contrast to the smaller /3-barrels of water-soluble proteins, those of membrane-inserted /3-barrels start at eight strands and run up to 22 (Table II). Presumably, the required tightly packed nonpolar barrel core of the water-soluble proteins limits the radius of circular barrels to small values. In contrast, transmembrane barrels form polar cores the stability of which depends on hydrogen bonds rather than on geometrically exact nonpolar packing contacts. Such polar cores can be constructed much more leisurely and may also include water molecules that increase... 

Figure 1 Schematic representation of the Fe-protein (60 kD, 2 dimer) and the MoFe-protein (250 kD, a2fh. tetramer) of the Mo-nitrogenase. Outline of the electron transfer path through the metal clusters. Structure of the Fe4S4 cluster of the Fe-protein. Structure of the P-cluster (in two oxidation states) and of the FeMo-cofactor in the MoFe-Protein. Limiting stoichiometry for the function of Mo-nitrogenase...

Fine glass beads (45-50 ju. diameter) also work well, but may tend to bind certain proteins, limiting their applicability. 

Tripadiy SK, Black HB, Goldwasser E, Leiden JM (1996) Immune responses to tr-ansgene-encoded proteins limit die stability of gene expression after injecdon of replicadon-defecdve adenovirus vectors. Nat Med 2 545-550. 

Thymol is a more powerful disinfectant than phenol, but its low water solubility, its irritancy to tissues, and its inactivation by organic material, such as proteins, limit its use as a disinfectant. Thymol is chiefly used as a deodorant in antiseptic... 

Minimum of 3 points must be linear (i.e., assay under protein limiting conditions). 

Plateau level of curve (in this case 900 cpm) should correspond to the maximum number of cpm transferrable from substrate to protein (usually 6% of total cpm see Subheading 3.1.3.). In some tissues (e.g., rat GIT) where protease activity is high, plateau levels may be lower than expected presumably owing to proteolytic degradation of the ATase. However, providing that specific activities are calculated based on the protein limiting (i.e., linear) part of the curve and all the above criteria are followed, reliable results may be obtained. 

Warshel, A., Russell, S.T. and Churg, A.K. (1984). Macroscopic models for studies of electrostatic interactions in proteins limitations and applicability. Proc. Natl. Acad. Sci. USA 81, 4785 4789... 

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