Halling P J, Dunnill P
Biotechnol Bioeng. 1979 Mar;21(3):393-416. doi: 10.1002/bit.260210304.
Ni powders coated by deposition of TiO2 or controlled oxidation to NiO develop substantial resistance to corrosion. Chymotrypsin immobilized to these coated Ni supports shows very high stability of activity on storage. Chymotrypsin immobilized by adsorption and glutaraldehyde crosslinking was fairly rapidly eluted under operational conditions in the presence of substrate. If 3-aminopropyltriethoxysilane (APS) was used to produce a covalent linkage, desorption of enzyme still occurred because of relatively unstable bonding of the silane to the oxide surface. A more stable attachment was produced by joining together many silane links with a layer of polyglutaraldehyde. The mechanism of action of APS as a coupling agent under these conditions is discussed. gamma-Fe2O3, and particularly a Mn-Zn ferrite, are suitable magnetic support materials available with smaller particle sizes. Particles below 1 mum give the expected higher specific activities of immobilized enzymes.
通过二氧化钛沉积或可控氧化为氧化镍包覆的镍粉对腐蚀具有显著抗性。固定在这些包覆镍载体上的胰凝乳蛋白酶在储存时显示出非常高的活性稳定性。通过吸附和戊二醛交联固定的胰凝乳蛋白酶在有底物存在的操作条件下相当迅速地被洗脱。如果使用3-氨丙基三乙氧基硅烷（APS）产生共价键，由于硅烷与氧化物表面的键合相对不稳定，酶仍会发生解吸。通过用一层聚戊二醛连接许多硅烷键产生了更稳定的附着。讨论了APS在这些条件下作为偶联剂的作用机制。γ-氧化铁，特别是锰锌铁氧体，是具有较小粒径的合适磁性载体材料。小于1微米的颗粒赋予固定化酶预期的更高比活性。
