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Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 CONT

The affinity label, N-tosyl-L-phenylalanylchloromethyl ketone (TPCK), was designed to resemble a normal substrate for chymotrypsin. However, instead of the usual susceptible structure of the substrate (-CO-NH-), TPCK contains the -CO-CH₂Cl group, a potent alkylating agent. Incubation of TPCK with chymotrypsin causes it to bind to the active site in the same way as the normal substrate. However, instead of hydrolysis of the substrate, alkylation of the essential His 57 residue occurs, indicating that the latter is close to the susceptible bond normally undergoing hydrolysis. The alkylated His residue can be isolated following complete hydrolysis of all the peptide bonds of the enzyme.  1, record 1, English, - TPCK

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 DEF

Composé qui mime la structure d'un résidu aromatique et qui réagit avec spécificité sur l'histidine de la chymotrypsine, entraînant ainsi l'inactivation de l'enzyme.  2, record 1, French, - TPCK

Record number: 1, Textual support number: 1 OBS

C'est grâce au TPCK si l'on a pu démontrer le rôle de l'histidyl 57 dans le fonctionnement de la chymotrypsine.  2, record 1, French, - TPCK

Record 1,  Textual support,  Spanish