Günter Blobel, a molecular biologist who was awarded the 1999 Nobel Prize in Medicine for discovering that proteins in any living cell have virtual ZIP codes that guide them to where they can help regulate body tissues, organs and chemistry, died on Sunday in Manhattan. He was 81.

A spokeswoman for Rockefeller University in Manhattan, where he was a longtime professor, confirmed his death, at NewYork-Presbyterian Weill Cornell Medical Center. The cause was cancer.

Because all diseases have a molecular basis, medical experts say, Dr. Blobel’s achievement was a fundamental step on the road to improved health, holding out the promise of understanding the mechanisms behind cystic fibrosis, Alzheimer’s disease, leukemia, schizophrenia, the virus that causes AIDS and other immune-system deficiencies, hereditary conditions and cellular aberrations, including cancers.

A Silesian-born boy in Nazi Germany during World War II, and later a refugee from postwar Communism in East Germany, Dr. Blobel (pronounced BLO-bull) set out to be a physician in America but found himself increasingly drawn to pure research. He spent nearly all his working life at Rockefeller University, what he regarded as the Valhalla of research.