His most significant scientific work involved synthetic peptides and their interactions with proteases; with his wife Sofia Simmonds he also published an influential textbook, General Biochemistry (1953; 1958).
[2] Between 1917 and 1923, Fruchtgarten attended school intermittently, moving from Minsk to Siedlce to Warsaw to Berlin, and learning French, German and Latin (in addition to Polish and English).
He applied to Columbia University, and after an initial rejection—possibly because he was only 15 at the time, possibly because the school had already admitted the quota of New York Jews—his mother convinced an admissions official to reverse the decision.
[5] Fruton's PhD work focused on "the lability of cystine in alkali", although he developed a broad interest in the range of biochemistry-related research being pursued at the College of Physicians and Surgeons.
Fruton joined a growing science faculty, which included the editor of the Journal of Biological Chemistry, Rudolph Anderson; biochemist Edward Tatum also came to Yale at the same time.
[11] By 1952, he was elected to the National Academy of Sciences,[12] and that year he also became chairman of the Department of Physiological Chemistry (which was renamed Biochemistry, reflecting the shift in research focus from medical to general biological problems).
The two main areas of research were the action of proteolytic enzymes and the chemical (as opposed to biological) synthesis of peptides (the substrates used to explore the enzymatic reactions).
Members of Fruton's lab studied cathepsin C and several other peptidases, as well as proteinases that catalyzed transpeptidation, which was thought (and ultimately confirmed) to be part of the biosynthesis of proteins.
Ph.D. students and postdoctoral researchers who worked in Fruton's lab include: Mary Ellen Jones, Melvin Fried, Hannelore Würz, Peter Heinrich, Karen Nilsson, Bob Metrione, Yoshihiro Okuda, George Taborsky, Christine Zioudrou, Maxine Singer, Louis Cohen, Frederick Newth, John Thanassi, Charles Drey, Derek George Smyth, Atsuo Nagamatsu, and Milton Winitz.
A number of prominent biochemists from outside Yale also spent time in Fruton's biochemistry department during his tenure as chair, including: Harry Kroll, Rosabelle McManus, John Clark Lewis, Herbert Gutfreund, Max Gruber, Frank Hird, Vernon Ingram, Hans Kornberg, Dimitrios Theodoropoulos, and Hans Tuppy.