Hans Walter Kosterlitz. 27 April 1903 — 26 October 1996

Hans Walter Kosterlitz will be remembered as the winner of an international race to identify the first endogenous opioid, enkephalin. He came to the UK from Berlin in 1934, one of the many scientific emigres of that period who later so enriched biochemistry, physiology and pharmacology. His entire career was spent at the University of Aberdeen, where he developed a reputation first in carbohydrate metabolism and later in the pharmacology of opiates. His strong experimental skills, and particularly the use of bioassays on tissues from laboratory animals, allowed him to predict the effectiveness and abuse potential of opiate drugs. Most notably, this led to the isolation of the peptide hormone enkephalin, the first of a group of such peptides now often known as endorphins. This work was done in his seventies, after his official retirement, with an energy and enthusiasm that could leave younger colleagues physically tired but intellectually stimulated.