TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 CONT

By 1920 most of the naturally occurring [alpha]-amino acids had been identified in hydrolyzates from crystalline proteins. Yet, the scientific community was far from adoption of a structural theory that would explain how enzymes are assembled from amino acid building blocks. In fact, the crystallization and characterization of urease as a protein by Summer ... in 1926 drew much scepticism from others who viewed the crystalline protein merely as an inert carrier of the catalytic agent. The issue was clouded by the recognition of other, nonprotein molecules closely associated with enzymes (prosthetic groups in today's terminology), and required for enzymatic activity. The identity of enzymes as proteins came conclusively from quantitative studies, such as partial proteolytic digestion and immunoprecipitation.... Today, X-ray crystallography is a vital tool for determining protein structure and its relationship to the catalytic action of enzymes.  1, fiche 1, Anglais, - crystalline%20protein

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 CONT

Pendant de nombreuses années on pensa que les protéines étaient les macromolécules biologiquement les plus importantes, ceci à cause de la découverte de la nature protéique des enzymes. Au début, la constitution des enzymes avait donné lieu à une controverse. S'agissait-il de petites molécules ou de macromolécules? Ce ne fut qu'en 1926 que la fonction enzymatique d'une protéine cristallisée fut démontrée pour la première fois par le biologiste américain Sumner; la controverse était alors pratiquement terminée.  1, fiche 1, Français, - prot%C3%A9ine%20cristallis%C3%A9e

Fiche 1,  Justifications,  Espagnol