Dr. Andrew C. Peacock, 63, a noted biochemical researcher who was an official of the National Cancer Institute, a part of the National Institutes of Health, died of cancer June 26 at the NIH clinical center. He lived in Rockville.

He began working for the National Cancer Institute at the University of Washington in 1949, and moved to this area and the institute's national headquarters in 1953. At the time of his death, he was protein section chief of the institute's Laboratory of Moleculcar Carcinogenesis.

In the 1960s, Dr. Peacock and two others developed the materials and methods for the process known as polyacrylamide gel electrophoresis (PAGE) used to separate nucleic acids.

NIH official Harry Gelboin said PAGE was "one of the methodologic foundations of modern molecular biology." Electrophoresis is used to separate and identify molecules of DNA and protein.

In recent years, Dr. Peacock had worked on a new technique, called two-dimensional gel electrophoresis, a process that should be used to further advance DNA analysis by making possible the study of the internal sequence of genes and the identification of substances that indicate genetic disorders.

Dr. Peacock was a native of Boston. He served with the Army Air Forces in the Pacific during World War II. He earned bachelor's and master's degrees and a doctorate in biochemistry at the Massaschusetts Institute of Technology.

He was the recipient of the Superior Service Honor Award of the old Department of Health, Education and Welfare. He was a member of the American Association of Cancer Research and the American Society of Biological Chemists. He was a volunteer with the Boy Scouts and a member of the Brookside chapter of the Azalea Society.

Survivors inlcude his wife of 41 years, Gloria, of Rockville; a son, Richard, of Reno, Nev.; two daughters, Carol Peacock of Watertown, Mass., and Nancy Peacock of Wood Dale, Ill.; a sister, Mary Peacock of Carlisle, Mass., and two grandchildren.