Peter G. Schultz (born June 23, 1956) is an American chemist, entrepreneur, and nonprofit leader. He is the CEO and president and Professor of Chemistry at Scripps Research, the founder and former director of GNF, and the founding director of the California-Skaggs Institute for Innovative Medicines, established in 2012. In August 2014, Nature Biotechnology ranked Schultz the #1 top translational researcher in 2013. Schultz's contributions to the field of chemistry have included the development and application of methods to expand the genetic code of living organisms, the discovery of catalytic antibodies, and the development and application of molecular diversity technologies to address problems in chemistry, biology, and medicine.

Schultz completed his undergraduate degree at Caltech in 1979 and continued there for his doctoral degree in chemistry (in 1984) with Peter Dervan. His thesis work focused on the generation and characterization of 1,1-diazenes and the generation of sequence-selective polypyrrole DNA binding/cleaving molecules. He then spent a year at the Massachusetts Institute of Technology with Christopher Walsh before joining the chemistry faculty at the University of California, Berkeley. He became a Principal Investigator of Lawrence Berkeley National Laboratory in 1985 and an investigator of the Howard Hughes Medical Institute in 1994. In 1999, Schultz moved to Scripps Research and also became founding Director of the Genomics Institute of the Novartis Research Foundation (GNF), which was initiated purely as a genomic research outlet of Novartis, but which grew during Schultz's tenure to include a significant drug discovery effort and more than triple the number of intended employees (currently over 500 people). In March 2010, he left GNF to return to the nonprofit sector and, in March 2012, founded the California Institute for Biomedical Research (Calibr), later renamed the Calibr-Skaggs Institute for Innovative Medicines. Schultz was named CEO of Scripps Research in 2015 and President the following year. He has trained over 300 graduate students and postdoctoral fellows, many of whom are on the faculties of major research universities.

Much of Schultz's work consists of finding ways to do a great many similar experiments at the same time, on many different compounds. He is one of the leading pioneers in combinatorial chemistry, screenable molecular libraries, and "high-throughput" chemistry. His interests are wide-ranging, with applications in such diverse areas as catalytic mechanisms, cell-specialization and other complex biological processes (normally studied by biologists, not chemists), basic photochemistry, biophysical probes of all stripes from NMR through positron-emission, and solid-state materials science.

Early in his career, Schultz showed that the natural molecular diversity of the immune system could be directed to generate catalytic antibodies. This method enabled the subsequent development of many new selective enzyme-like catalysts for reactions ranging from acyl transfer and redox reactions to pericyclic and metalation reactions. Although their catalytic activities are only rarely strong enough to be of practical use, catalytic antibodies have provided important new insights in our understanding of biocatalysis, structural plasticity of proteins, evolution of biochemical function, and the immune system itself.

Schultz then applied molecular diversity—the strategy of creating a large community of different molecules, plus a method for fishing out and identifying the ones that do what you want—to a range of problems in chemistry, biology and materials science. Along with Richard Lerner, he was one of the critical players in the development of phage-display libraries, and surface-library chips. For high-throughput bioassays which require freely soluble test-compounds, he uses microrobotic fluid-manipulation systems, adapted for 1,536-microwell cell-culture plates, to separately treat very small cell colonies with large numbers (hundreds of thousands) of different compounds.

Using these various high-throughput and combinatorial experimental approaches, Schultz has identified materials with novel optical, electronic, and catalytic properties; also, proteins and small molecules which control important biological processes such as aging, cancer, autoimmunity, and stem-cell differentiation and de-specialization back to pluripotency.

Schultz has pioneered a method for adding new building blocks, beyond the common twenty amino acids, to the genetic codes of prokaryotic and eukaryotic organisms. This is accomplished by screening libraries of mutant amino acyl tRNA synthetases for mutants which charge nonsense-codon tRNAs with the desired unnatural amino acid. The organism which expresses such a synthetase can then be genetically programmed to incorporate the unnatural amino acid into a desired protein in the usual way, with the nonsense codon now coding for the unnatural amino acid. Normally, the unnatural amino acid itself must be synthesized in the lab and supplied to the organism by adding it to the organism's growth medium. The unnatural amino acid must also be able to pass through the organism's cell membrane into the interior of the organism.

More than 70 unnatural amino acids have been genetically encoded in bacteria, yeast, and mammalian cells, including photoreactive, chemically reactive, fluorescent, spin-active, sulfated, pre-phosphorylated, and metal-binding amino acids. This technology allows chemists to probe, and change, the properties of proteins, in vitro or in vivo, by directing novel, lab-synthesized chemical moieties specifically into any chosen site of any protein of interest.