Philip Siekevitz

Over fifty years of research have focused initially on amino acid metabolism, in vitro protein synthesis by subcellular fractions, and oxidative phosphorylation by mitochondria. He then spent twenty years as the biochemical member with the electron microscopist, George Palade, in joint projects on the membranes and ribosomes of the endoplasmic reticulum, isolated as microsomes. They studied the role of the ribosomes in protein synthesis, and the role of the membranes in the pancreatic secretory pathway of the newly-synthesized proteins. At the same time, they studied the differentiation and development of these membranes in liver, concentrating on the membrane enzymes. Finally, he switched to the nervous system, doing cell biological studies on an organelle called the postsynaptic density located at synapses of the central nervous, examining the structure and chemical and biochemical components involved with nerve signal conduction which are located there.