scholarly journals The determination of the molecular weight of ribonucleic acid by polyacrylamide-gel electrophoresis. The effects of changes in conformation

1969 ◽  
Vol 113 (1) ◽  
pp. 131-138 ◽  
Author(s):  
U E Loening
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sedimentation Coefficient ◽  
Nucleotide Composition ◽  
Polyacrylamide Gel ◽  
Relative Mobility ◽  
Experimental Conditions ◽  
Low Ionic Strength

1. The effects of changes in experimental conditions on the mobility of RNA in polyacrylamide-gel electrophoresis were investigated. 2. The linear relation between log(molecular weight) and electrophoretic mobility was shown to be independent within limits of salt or gel concentration. 3. The relative mobility of RNA with low content of guanylic acid and cytidylic acid residues was decreased in low-ionic-strength buffer. This was related to a small relative decrease in sedimentation coefficient. 4. However, Mg2+ ion caused almost no increase in mobility although it was associated with large increases in sedimentation coefficient. This suggested opposing actions of Mg2+ ion on the size and effective charge of the RNA. 5. It is concluded that the method provides a satisfactory measurement of molecular weight, which is almost independent of the nucleotide composition of RNA at moderate salt concentrations.

scholarly journals Anomalous migration of leghaemoglobin on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis

1978 ◽  
Vol 169 (1) ◽  
pp. 251-253 ◽  
Author(s):  
P Lehtovaara
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Relative Mobility ◽  
Concomitant Decrease ◽  
Helical Content

The estimate of the molecular weight of leghaemoglobin by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis is about 20% too low. This is due to an anomalously high limiting relative mobility. Leghaemoglobin binds 1.4 g of sodium dodecyl sulphate/g of protein with a concomitant decrease in the helical content from 71-72% to 49-51%.

scholarly journals Molecular weight estimation of esterase isoenzymes in closely related Drosophila Species (Diptera: Drosophilidae) in non-denaturing polyacrylamide gel electrophoresis

2009 ◽  
Vol 52 (5) ◽  
pp. 1083-1089 ◽  
Author(s):  
Rogério Pincela Mateus ◽  
Hamilton Cabral ◽  
Gustavo Orlando Bonilla-Rodriguez ◽  
Carlos Roberto Ceron
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Duplication Event ◽  
Polyacrylamide Gel ◽  
Molecular Weight Determination ◽  
Structural Genes ◽  
Repleta Group ◽  
Native Polyacrylamide Gel Electrophoresis

A method that allows the measure of molecular weight of two well-known and closely related esterases from Drosophila mojavensis and its sibling species, D. arizonae, is here described, using native polyacrylamide gel electrophoresis at several concentrations, applying Fergunson´s principles. These enzymes, namely EST-4 and EST-5, presented molecular weight values between 81 and 91 kDa. In spite of their distinct expression pattern through the insect's life cycle, they showed properties of isoenzymes codified by distinct structural genes, supporting the hypothesis of a rather recent gene duplication event that generated both in D. mojavensis and D. arizonae, as well as in other species of repleta group. The method is simple and adequate to be applied to preliminary molecular weight determination of other enzymes without any previous purification procedure.

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