Screening The Inhibiting Effect Of ACE From Food And Its Separation And Purification

Because a large number of people suffer from high blood pressure,it is unclear which foods can alleviate hypertension.Angiotesin-Converting Enzyme(ACE),as a key enzyme regulating blood pressure in the renin-angiotensin system,is a key role for the study of hypertension drugs.In this paper,ACE was isolated and extracted from pig lung,and its extraction conditions was optimized for preparing ACE crude enzyme solution.Different food-borne raw materials were extracted by water,alcohol and protease enzymatic hydrolysis,for inhibiting ACE.The food with potential ability to suppress hypertension were screened.Because broccoli protease hydrolysate was strongest sbility than others for inhiting ACE enzyme.It is selected and analyzed by various chromatographic techniques and mass spectrometry techniques.The main findings are as follows:The experiments were carried out by a variety of different buffers,with or without adding 2%trypsin as pretreatment for porcine lung ACE extraction,The resules showed that the highest ACE enzyme activity was got by homogenate with 100g pig lung and 500mL 0.1 M,pH 8.3 borate buffer without trypsin,and the ACE activity extracted from 100g pig lung was 36.4 U.Combined with ultrasound-assisted extraction technology,for obtaining more ACE enzyme was studied.The ultrasound conditions of 140w,160w,180w,200w ultrasonic power for 3min,5min,7min,10min were experimented.The optimum condition was 180w for 5 min.To keep the enzyme vitality,the effect of protective agents on ACE enzyme activity during lyophilization was investigated.The dialysis were added with 5%glucose,5%sucrose,5%glycerol and 5%bovine serum albumin respectively as lyoprotectant.The glucose group was found protective effect,which was 14.3%higher than that of the control group;bovine serum albumin group was almost ineffective,and the ACE enzyme activity of adding sucrose or glycerol groups was decreased.100 kinds of foods were extracted with water,or absolute ethanol or protease hydrolysis to prepare different extracts were used to inhibit ACE enzymes.After two round screenings experiment,the enzymatic hydrolysates of broccoli,garlic and spinach had higher ACE inhibitory activity than others,and their △U/protein(×0.1U/mg)values were 0.627,0.534 and 0.508,respectively;The aqueous extracts of pleurotus ostreatus and kiwifruit also have higher ACE inhibitory activity,and the AU/fresh weight(×0.1U/g)values were 2.237 and 2.874,respectively;In vivo digestion simulation test verifies showed that the enzymatic hydrolysates of broccoli,garlic and spinach were not inactivation after intestinal digestion.The inhibition rate of ACE enzyme activity was 53%,44%and 38%respectively;Three extracts of the five aqueous and protease hydrolysis extracts were mixed with equal volunes,and was found the three enzymes compound had the best ability,which inhibition rate was 65%.Since the broccoli protease enzymatic extract had the strongest inhibition of ACE enzyme activity in the three extraction methods of 100 foods.The enzymatic extract of broccoli was isolated and purified.After gel filtration chromatography and preparative and analytical HPLC,The component BHs-Ⅳ-Ⅲ-Ⅳ had the highest ACE inhibitory activity.After identification by ESI/MS,the polypeptide was found having a molecular weight of 834.5Da and a primary structural sequence of Ly s-S er-Val-Leu-Leu-Ly s-Phe.