Partial purification and properties of flyhead cholinesterase

Housefly head cholinesterase was purified using the following steps: (1) freeze-drying of flyheads, (2) solubilization of the enzyme by butanol extraction, (3) ammonium sulphate precipitation at pH 7, (4) heat denaturation of proteins in the presence of acetylcholine for protection of the cholinesterase, (5) ammonium sulphate fractionation at pH 7 and at pH 6, (6) calcium phosphate gel absorption and elution, and (7) acetone fractionation. The final preparation, a solution in glass-distilled water, hydrolysed acetylcholine at a rate of 1600 μM/hr/mg of organic matter (157 × purification). It proved fairly stable and was used for studying some properties of the enzyme. The substrate specificity did not change much in the course of purification. The purified enzyme differed from purified bovine cholinesterase in that it hydrolysed butyrylcholine, triacetin, and phenylbutyrate at a much higher rate. The evidence strongly points to one single enzyme being responsible for the hydrolysis of all substrates studied, including butyrylcholine. Inhibition experiments with organophosphates indicate a probable turnover number in acetylcholine hydrolysis of about 100,000. Experiments on the influence of organic solvents showed that 2–3% n-butanol increases the enzymic activity on choline esters about 60%, and that n-butanol, acetone, and ethanol all lower the rate of inhibition by an organophosphorus compound (diazoxon). Agar gel electrophoresis at pH 8·4 showed the cholinesterase to migrate, probably together with other proteins still present in the purified preparation, at a speed which is about 0·9 times the speed of human serum albumin

Clinical features and contemporary management of patients with low and preserved ejection fraction heart failure: baseline characteristics of patients in the Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) programme.

Aims: To describe the clinical characteristics and contemporary treatment of a broad spectrum of patients with chronic heart failure (CHF) randomised in the Candesartan in Heart failure—Assessment of Reduction in Mortality and morbidity (CHARM) programme, consisting of three component studies comparing placebo to candesartan.<p></p> Methods and results: CHARM Alternative, CHARM Added and CHARM Preserved enrolled 2028 low left ventricular ejection fraction (LVEF) ACE inhibitor intolerant patients, 2548 low LVEF ACE inhibitor treated patients and 3025 preserved LVEF patients, respectively. Patients in CHARM Preserved were more often female. The proportion of women in CHARM Preserved was 40% compared to 32% in CHARM Alternative and 21% in CHARM Added. Patients in CHARM Preserved were also more often hypertensive than in the other two trials (64% vs. 50% and 48%, respectively). Symptoms and signs (with the exception of a third heart sound) were similar in all three patient groups. Beta-blockers were used in over half of patients in all three groups. Digoxin and spironolactone were used less frequently and calcium antagonists more frequently in CHARM Preserved. Spironolactone was used most frequently in CHARM Alternative, i.e. in ACE inhibitor intolerant patients.<p></p> Conclusions: The CHARM Programme provides the largest and most detailed comparison to date of patients low- and preserved-LVEF CHF. It also describes the causes of ACE-inhibitor intolerance in a large cohort of patients and the other treatment which these patients receive