Konrad E. Bloch, 88, Nobelist Who Studied Cholesterol, Dies

Dr. Konrad E. Bloch, who won a Nobel Prize for explaining how cholesterol is formed in the body, died Sunday at the Lahey Clinic in Burlington, Mass. He was 88 and lived in Lexington, Mass.

When Dr. Bloch won the Nobel, in 1964, the Karolinska Institute in Sweden, which chooses the recipients of the prize in physiology or medicine, cited him for ''a series of brilliant investigations'' that discovered how cholesterol develops from acetic acid via a complex sequence of about 36 biochemical reactions. Dr. Bloch shared the prize with Dr. Feodor Lynen, a German who independently discovered the biosynthesis of cholesterol.

The prize was awarded as scientists began warning that excessive cholesterol could contribute to circulatory diseases like atherosclerosis, in which the arteries narrow, leading to a heart attack or a stroke. The work of Dr. Bloch and Dr. Lynen eventually allowed researchers to design drugs called statins that block the process that produces cholesterol. Although egg yolks and other foods contain high amounts of the substance, most of the cholesterol circulating in the body is produced by built-in cholesterol factories in the liver.

''It's impossible to imagine cholesterol without Bloch; without his work we would know almost nothing,'' said Dr. Michael S. Brown, a researcher at the University of Texas Southwestern Medical Center, who with Dr. Joseph L. Goldstein won the Nobel Prize in Physiology or Medicine in 1985 for showing how cholesterol is absorbed by human body cells.

Dr. Bloch ''laid out the basic pathway, and we wanted to see how that pathway was turned on and off,'' Dr. Brown said.

Konrad Emil Bloch was born in 1912 in Neisse, Germany, which is now Nysa, Poland. He earned a degree in chemistry in Munich, but because he was Jewish, the Nazis prevented him from undertaking further study, and he moved to Switzerland in 1934. Two years later, he came to the United States, earning a doctorate in biochemistry at Columbia University, where he began researching the synthesis of cholesterol, work that he continued when he became a professor at the University of Chicago in 1946.

Although cholesterol is best known for its harmful effects, it is also essential for life, playing a role in all cellular functions. The substance had been identified in 1820, but its formation was a mystery.

At the time Dr. Bloch began his research, cholesterol was receiving little attention, said Dr. Valentin Fuster, director of the cardiovascular institute at the Mount Sinai School of Medicine and former president of the American Heart Association. ''He was very intuitive that cholesterol was important in disease.''

Taking advantage of recent advances in physics, Dr. Bloch used the isotope deuterium to determine that acetic acid is a precursor of cholesterol in rats. From there, he learned that acetic acid converts to a hydrocarbon called squalene, which becomes a steroid called lanosterol, which turns into cholesterol.

Dr. Bloch became the Higgins professor of biochemistry at Harvard in 1954, a position he held until his retirement in 1982. From 1968 to 1972, he was the chairman of the biochemistry department. He was also a professor in Harvard's School of Public Health from 1979 to 1984.

In addition to his other honors, Dr. Bloch was awarded the National Medal of Science in 1988. In 1994, he published ''Blondes in Venetian Paintings, the Nine-Banded Armadillo and Other Essays in Biochemistry'' (Yale University Press).

He is survived by his wife of 49 years, the former Lore Teutsch; a son, Peter, of Madison, Wis.; a daughter, Susan, of Philadelphia; a brother, Hans, of Somers, N.Y.; and two grandchildren.