Molecular weight of polypeptide

See, Y.P., Jackowski, G. (1989) Estimating molecular weights of polypeptides by SDS PAGE, in Protein Structure (Creighton, T.E., Ed.). IRL Press, Oxford. 

TLC of proteins and polypeptide chains on cross-linked dextran gel (such as Sephadex) as described by Determann (28), Jaworek (29), and others (30), provides a method that allows estimation of molecular weights of polypeptides in a much shorter time since Andrews (31) has found a close correlation between the logarithm of the molecular weight of a protein and its chromatographic... 

Detectors such as those based on on-line light-scattering, UV absorbance, or refractive index measurements are employed to characterize the molecular weights of polypeptides, simple proteins, and glycoproteins or to determine the stoichiometry of protein complexes [22],... 

Factor XIII. Factor XIII circulates in the blood as a zymogen composed of two pairs of different polypeptide chains designated A and B. Inert Factor XIII has a molecular weight of 350,000 daltons and is converted to its active transglutaminase form in the presence of thrombin and calcium. Activated Factor XIII, Xllla, induces an irreversible amide exchange reaction between the y-glutamine and S-lysine side chains of adjacent fibrin... 

The electron transport protein, cytochrome c, found in the mitochondria of all eukaryotic organisms, provides the best-studied example of homology. The polypeptide chain of cytochrome c from most species contains slightly more than 100 amino acids and has a molecular weight of about 12.5 kD. Amino acid sequencing of cytochrome c from more than 40 different species has revealed that there are 28 positions in the polypeptide chain where the same amino acid residues are always found (Figure 5.27). These invariant residues apparently serve roles crucial to the biological function of this protein, and thus substitutions of other amino acids at these positions cannot be tolerated. 

Structural Formula Has folded polypeptide chain of 212 residues with a molecular weight of about 23/too. 

MALDI-ToF is a technique that allows the molecular weights of proteins and peptides to be determined. It is less susceptible to suppression effects than electrospray ionization and thus is able to be used for the direct analysis of mixtures. In the case of a crude tryptic digest, MALDI-ToF will provide a molecular weight profile of the polypeptides present without the analysis time being extended by the need to use some form of chromatographic separation. 

Attempts were then made, using these data, to identify the proteins by searching against known peptide databases, such as ProFound [14], PepSea [15] and MSFit [16] that contain the molecular weights of theoretically expected polypeptides obtained from a known protein using a specific enzyme. The molecular weights... 

From a mass spectrometry perspective, these modifications, such as phosphorylation or glycosylation, manifest themselves as an increase in the molecular weight of both the parent protein and also of the polypeptides (produced by enzymatic digestion) containing the modification. 

The electrospray spectrum from the corresponding chromatographic response in the LC-MS analysis of the tryptic digest of the protein after reaction with the inhibitor is shown in Figure 5.24. In addition to the three species found in the digest of the parent protein, two additional polypeptides, with molecular weights of 2439.36 zb 0.07 and 2457.43 zb 0.02 Da, i.e. 70 and 88 Da above... 

The induction of anaerobic treatment synthesis occurs in two phases. During the first few hours of anaerobic treatment there is a transition period during which there is a rapid increase in the synthesis of a class of polypeptides with an approximate molecular weight of 33 kDa (Fig. 3). These have, been referred to as the transition polypeptides (TPs) as they represent most of the protein synthesis occurring in early anaerobiosis. 

It can be concluded that MD is a very powerful tool to refine structures of proteins and polypeptides in solution, based on 2D NMR data. This combination of techniques emerges as an important means to determine the 3 D structure of macromolecules up to a molecular weight of 20,000 in solution or in micelles or membrane fragments. 

Finally, to produce the structural and functional devices of the cell, polypeptides are synthesized by ribosomal translation of the mRNA. The supramolecular complex of the E. coli ribosome consists of 52 protein and three RNA molecules. The power of programmed molecular recognition is impressively demonstrated by the fact that aU of the individual 55 ribosomal building blocks spontaneously assemble to form the functional supramolecular complex by means of noncovalent interactions. The ribosome contains two subunits, the 308 subunit, with a molecular weight of about 930 kDa, and the 1590-kDa 50S subunit, forming particles of about 25-nm diameter. The resolution of the well-defined three-dimensional structure of the ribosome and the exact topographical constitution of its components are still under active investigation. Nevertheless, the localization of the multiple enzymatic domains, e.g., the peptidyl transferase, are well known, and thus the fundamental functions of the entire supramolecular machine is understood [24]. 

Heliantholysin. The major form of heliantholysin is a basic polypeptide chain (pi in the region of 9.8) having a molecular weight of 16,600. Its amino acid sequence has been determined (11). It is powerfully hemolytic for washed erythrocytes derived from a variety of animals, those of the cat being the most sensitive, and those of the guinea pig the most resistant (10). As is true of most hemolytic systems, the biochemical basis for the very large differences in sensitivity of erythrocytes from different animal species is unknown. 

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