Reversible interaction of metrizamide with protein

Metrizamide, a new density‐gradient medium

“…However, a significant proportion of the protein bands at densities between 1.37 and 1 SO g/cm3, that is, at densities greater than that of dehydrated protein [2]. This effect is seen with both monomeric and polymeric proteins, and simple and conjugated proteins, and we have shown that it is due to a transitory association of metrizamide with the protein [9]. This interaction is extremely weak (Kdi, > lo-' M), and completely reversible [9].…”

“…This effect is seen with both monomeric and polymeric proteins, and simple and conjugated proteins, and we have shown that it is due to a transitory association of metrizamide with the protein [9]. This interaction is extremely weak (Kdi, > lo-' M), and completely reversible [9]. The evidence available suggests that the interaction is between the iodinated aromatic nucleus of metrizamide and the protein [IO].…”

“…When protein is centrifuged to equilibrium in metrizamide, much of the protein bands at 1.27 g/cm3 [9] which is somewhat lower than the buoyant density in CsCl, but which corresponds to fully hydrated protein [2,9] (table 1). However, a significant proportion of the protein bands at densities between 1.37 and 1 SO g/cm3, that is, at densities greater than that of dehydrated protein [2].…”

Isolation of the intercellular glycoproteins of desmosomes.

“…It has been used in a variety of purification procedures for organelles and macromolecules (reviewed in reference 24). Previous studies have shown that metrizamide at high concentrations interacts reversibly with proteins to form dense complexes (10,25). Rickwood and Jones (26) have presented the most detailed study to date of the interaction of metrizamide with proteins, showing that high concentrations of metrizamide promote the release of proteins from ribosomes.…”

Isopyenic centrifugatian of sheared L-cell chromatin in metrizamide gradients

“…This solution was made 1% with mercaptoethanol and SDS and incubated at 0~~~~~~~3 60°C for 30 minutes. The H-histone and NHP's were then dialyzed against 0.1% SDS, 0.1% mercaptoethanol, 0.01 M sodium phosphate pH 7.0 and analyzed by electrophoresis on 15 7.5% acrylamide gels . Figures 4a and b show the electrophoretic distribution of 3H-leucine labeled proteins obtained from chromatin isolated from detergent and citric acid extracted nuclei respectively.…”