Polypeptides molecular weight

DNA binding properties and polypeptide molecular weights of receptors... 

The molecular weight is approximately 11,900, the sum of the polypeptide molecular weight (approx. 104 x 110) and that of the heme prosthetic group (412). Alternatively, the molecular mass is approx. 11.9 kDa. 

Protein Sequencing Mass Spectrometry Proteins were sequenced on an Applied Biosystems 477A protein sequencer. Polypeptide molecular weights were determined after analysis by a Sciex API-Ill electrospray ioniziation mass spectrometer. 

The aminocellulose powder is initially dissolved in ammoniacal cupric hydroxide and reprecipitated to produce a flocculent suspension. In this form it is converted to the diazonium derivative with nitrous acid and immediately allowed to react with protein. The following quantities are adequate for the binding of up to 500 mg of protein assuming a molecular weight of the protein of approximately 100,000. For small polypeptides (molecular weight in the region of 10,000 or less) these quantities would only be sufficient to react with 50 mg of peptide. 

Polypeptide molecular weights do not include carbohydrate contributions. 

Other Variables. The effect of the polypeptide molecular weight upon a has not yet been conclusively established for any polypeptide-organic solvent system. Recent extensive studies of the charge-induced transition of polyglutamic acid in aqueous solution have shown an increase in a with a reduction in molecular weight 15). Similarly the influence of polypeptide solute concentration is not yet clear, though Ackermann and Riiterjans 1) have demonstrated a remarkably large effect of this variable upon AH0 in PBG. Neither of these points is discussed further in the present paper. 

Vegetative microplasmodia of the slime mould, Physarum polycephalum, have been shown to introduce an intracellular i3-D-2-acetamido-2-deoxy-hexosidase. Under certain conditions extracellular activity was also produced. Evidence demonstrating dissimilarities between the two enzymes included marked differences in specificities for natural and synthetic substrates, kinetic parameters, relative net charges, carbohydrate contents, subunit polypeptide molecular weights (extracellular 2.53 x 10, intracellular 4.05 x 10 ), amino-acid compositions, and immunological properties. The apparent distinct nature of the structural genes coding for the enzymes was discussed. 

Description. These surfactants are formed from hydrolyzed proteins (e.g., animal coUagen). Depending on the protein hydrolysis process (chemical or enzymatic), the average polypeptide molecular weight can vary from about 350 to 2000 and some free amino acids may be present in the hydrolysate. 

Fig. 3. Sodium dodecyl sulfate—polyacrylamide gel electrophoretic pattern for molecular weight standards (lane 1) water-extractable proteins of defatted soybean meal (lane 2) purified IIS (glycinin) (lane 3) and purified 7S (P-conglycinin) (lane 4) where the numbers represent mol wt x 10. The gel was mn in the presence of 2-mercaptoethanol, resulting in the cleavage of the disulfide bond linking the acidic (A bands) and basic (B bands) polypeptides of the...

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 reaction center is built up from four polypeptide chains, three of which are called L, M, and H because they were thought to have light, medium, and heavy molecular masses as deduced from their electrophoretic mobility on SDS-PAGE. Subsequent amino acid sequence determinations showed, however, that the H chain is in fact the smallest with 258 amino acids, followed by the L chain with 273 amino acids. The M chain is the largest polypeptide with 323 amino acids. This discrepancy between apparent relative masses and real molecular weights illustrates the uncertainty in deducing molecular masses of membrane-bound proteins from their mobility in electrophoretic gels. 

It follows, that the peak width of a solute could give an indication of its molecular weight and, although the data may not be precise, approximate values could be extremely valuable when dealing with very large molecular weight substances such as polypeptides and proteins. In particular, the technique would be very useful for those substances that are extremely difficult, or impossible, to vaporize in the ion source of a mass spectrometer to provide mass data. 

Amino acid analysis itself does not directly give the number of residues of each amino acid in a polypeptide, but it does give amounts from which the percentages or ratios of the various amino acids can be obtained (Table 5.2). If the molecular weight and the exact amount of the protein analyzed are known (or the number of amino acid residues per molecule is known), the molar ratios of amino acids in the protein can be calculated. Amino acid analysis provides no information on the order or sequence of amino acid residues in the polypeptide chain. Because the polypeptide chain is unbranched, it has only two ends, an amino-terminal or N-terminal end and a carboxyl-terminal or C-termuial end. 

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. 

Most aspartic proteases are composed of 323 to 340 amino acid residues, with molecular weights near 35,000. Aspartic protease polypeptides consist of... 

Chemicai Name Polypeptide of molecular weight approximately 3,550 see Structural Formula... 

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