Gadzira shanduro yakaoma kunzwisisa yemutsara uyu Muna 1929, Northrop yakazviparadzanisa nekristallisa enzyme yegastric pepsin ndokusarudza kuti yaiva protein.
Chokwadika, shanduro yakaoma kunzwisisa zvikuru yemutsara wacho ndeiyi "Muna 1929, akaparadzanisa uye akaenzanisa enzyme yegastric pepsin ndokusarudza kuti yakanga iri puroteni uye muna 1938 akaparadzanisa uye akaenzanisa bacteriophage yokutanga (utachiona huduku hunorwisa mabhakitiriya), uye akasarudza kuti yakanga iri nucleoprotein. "