微生物法生产丙烯酰胺的生物催化剂——腈水合酶研究进展

回顾了近年来国内外在微生物法生产丙烯酰胺的生物催化剂腈水合酶的结构、催化机理、光活性、热稳定性等方面的研究进展 .腈水合酶的活性部位含有螯合的金属离子作为辅助因子 ;结合金属离子的活性中心在腈水合酶的催化反应中起着重要的作用 ;其中铁型腈水合酶具有光活性 ,其活性是通过NO调节的 :在非活性腈水合酶的铁中心上连有一个内生的NO分子 ,在光的作用下 ,NO释放出来 ,使酶的活性恢复 .进一步探讨了温度对不同菌株酶活稳定性以及氨基化合物等因素对酶活性的影响 ,并对研究的发展方向提出了一些设想

ADVANCES OF NITRILE HYDRATASE USEDIN BIOCONVERSION FOR ACRYLAMIDE

Nitrile hydratase (NHase) is the biocatalyst which has been used in industrial bioconversion of acrylonitrile to acrylamide using microorganisms.Recent advances in the studies on structure,mechanism,photoreactivity,thermostability,etc.about NHases are reviewed.NHases contain metallic ions,which act as accessory factors in the active sites.The metal-binding sites play a crucial role in the enzymatic reaction.The photoactivation mechanism of Fe-type NHases is clarified.An endogenous NO is bound to the non-heme iron in the inactive NHase and its photodissociation activates the enzyme.From a practical point of view, the Nhases previously reported are still unsatisfactory catalysts because of their relatively low thermostability and the availability of some thermostable Nhases will help to reduce the inactivation of the enzyme.It is also clarified that amide compounds are essential for subunit assembly to yield active NHases.Some other factors are also discussed in this paper.Some perspectives on future research of NHase are presented.