Peptide diazomethyl ketones are inhibitors of subtilisin-type serine proteases.

Peptide diazomethyl ketones, well known as specific cysteine protease inhibitors are also potent inhibitors of the microbial serine proteases thermitase (EC 3.4.21.14) and subtilisin Carlsberg (EC 3.4.21.14). The affinity of the enzymes towards the synthetic inhibitors Z-Ala(n)-PheCHN2 (n = 0, 1, 2) depends on the chain length and is in the same range as for the corresponding chloromethyl ketones. Both kinds of inhibitors react irreversibly in a 1:1 ratio with the enzymes and covalently bind to the active site histidine of both subtilisin Carlsberg and thermitase despite the fact that thermitase contains an active-site cysteinyl residue. The mechanism of the inhibition reaction is discussed.

Induction and recovery characteristics of isoflurane and halothane anaesthesia for short outpatient operations in children.

Induction and recovery characteristics of isoflurane anaesthesia were compared with halothane anaesthesia during outpatient myringotomy and placement of Sheely ventilation tubes in 101 unpremedicated children. Compared with halothane, isoflurane resulted in prolonged induction times and inferior induction scores due to increased salivation, coughing, breathholding and laryngospasm. However, when modified by halothane induction, isoflurane anaesthesia decreased induction time and improved induction scores. Induction with thiamylal 4 mg/kg did not improve induction scores significantly. Recovery times from halothane plus isoflurane and pure isoflurane anaesthesia were quicker than pure halothane and thiamylal plus isoflurane, although this was not statistically significant. Compared to halothane, anaesthetic induction using isoflurane is associated with an increased incidence of respiratory problems in unpremedicated children.