13C Nuclear magnetic resonance of protamines. The three main components of clupeine.

The three main components (called YI, YII and Z) of clupeine a protamine from herring have been isolated and characterized by 13C nuclear magnetic resonance. Resonance belonging to the many different amino acid carbon atoms are observable and assigned. The effect of urea on the clupeine fractions points to the molecules being essentially in extended form in 2H2O solutions. Unusual properties of clupeine fractions can be observed in the presence of phosphate. Two of the fractions, i.e. YI and Z, show that a partial folding occurs in some well-defined whereas fraction YII remains essentially unaltered.