1. Human kidney mRNA species were isolated and fractionated through a continuous sucrose gradient ultracentrifugation.
2. mRNA fractions were translated by using a rabbit reticulocyte lysate and [35S]metbionine as tracer. Double immunoprecipitation was carried out with highly specific anti-human renin and anti-rabbit γ-globulin antisera.
3. A 15S mRNA has been found to direct synthesis of a 45 000 molecular weight protein immunoprecipitable with anti-human renin. This protein is considered to be the ultimate precursor of renin (preprorenin).