从桔青霉M71生产核酸酶P_1及酶活提高途径的研究

STUDIES ON THE PRODUCTION OF NUCLEASE P1 FROM PENICILLIUM CITRINUM M71 AND THE WAYS TO IMPROVE ENZYME ACTIVITY

由桔青霉Ｍ７１在２８±１℃下用深层通气搅拌发酵产生的核酸酶Ｐ１能降解热变性ＤＮＡ和酵母ＲＮＡ成为５＇－脱氧核苷酸和５－核苷酸。培养过程中酶活力高峰期在７０－９５ｈ之间，该酶对热变性ＤＮＡ和酵母ＲＮＡ的活力分别高达１５５ｕｎｉｔ／ｍｌ和３６９ｕｎｉｔ／ｍｌ，其最适作用温度为７５℃，最适ｐＨ值为５．０，在７０℃以下１ｈ之内稳定。发酵过程中控制接种量、氧气供应量、ｐＨ值及添加适量的Ｚｎ２＋，Ｆｅ２＋，Ｓｎ２＋，ＳＬ－Ｃｙｓｔｅｉｎｅ，Ｔｗｅｅｎ８０。

Nuclease P1 is Produced from Penicillium citrinum M71 strain by deep culture under aeration and stir at 28 ±1℃ . The enzyme can degrade heat-denatured DNA and yeast RNA into 5' -mononucleotides and 5' - deoxyribotide. The peak of enzymic yield in culture medium is observed at 70 - 95hrs. For heat denatured DNA or yeast RNA, the activity of the enzymc respective reach 155 unit/ml or 369 unit/ml. The optimum temperature optimum and pH for enzyme reaction respective is 75℃ and 5.0, and it is stable in one hour below 70℃ . Futher, the enzyme activity may greatly increased if the mould amounts , oxygen supply, pH and Zn2+. , Fe2+ , Sn2+ , L-Cysteine, Tween-80, pao-di (triatomic alcohol polyether) amounts be controlled.