کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8327045 | 1540197 | 2018 | 35 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Synthesis and characterization of cross linked enzyme aggregates of serine hydroxyl methyltransferase from Idiomerina leihiensis
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
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چکیده انگلیسی
A thermo-stable purified serine hydroxymethyltransferase (SHMT; 418 AA) was used for the carrier free immobilization using pectin as a coach molecule and formaldehyde as a cross-linker. The purified protein was cross linked with formaldehyde in the presence of pectin to form stable and active aggregates. The cross-linked enzyme aggregates [CLEAs] of SHMT showed improved catalytic properties and reusability. The SHMT-CLEAs showed a noteworthy change in the thermo-stability and activity compared to its free counterpart. The optimum activity for free SHMT was reported at 55â¯Â°C and pHâ¯7.5 which SHMT CLEAs showed maximum activity at 60â¯Â°C and pHâ¯8.0. Similarly, the CLEAs were noticed to increase the thermo-stability in comparison to free enzyme. The divalent salt ion Ca2+ and Ba2+ were found to enhance the activity at 1 and 5â¯mM of concentrations while Ni+, Co2+ and Zn2+ strongly inhibited the activity of both free as well as CLEAs. The Vmax and km values for free SHMT were recorded to be 1.21â¯Î¼Mâ¯sâ1 and 272â¯Î¼M while for CLEAs Vmax 1.42â¯Î¼Mâ¯sâ1 and km 248.6â¯Î¼M was recorded. Thus, a 120% increase in the Vmax was recorded for SHMT-CLEAs. The CLEAs were also found to be more stable at pHâ¯6.5 and 8.5 pHs and retained 50% of its original activity for 180 and 200â¯min respectively. The CLEAs also retained 72% of its activity after 12 repetitive cycles of d-phenylserine hydrolysis. Also, the synthesized CLEAs retained more than 60% of its original activity after 10â¯days of incubation at 25â¯Â°C in comparison to free enzyme which loses more than 90% of its residual activity. Thus, with improved thermostability and activity the CLEAs of SHMT can be used repetitively at industrial scale for the synthesis of commercially important amino acids.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Biological Macromolecules - Volume 117, 1 October 2018, Pages 683-690
Journal: International Journal of Biological Macromolecules - Volume 117, 1 October 2018, Pages 683-690
نویسندگان
Ashok Kumar, Gaobing Wu, Ziduo Liu,