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A thermostable S-adenosylhomocysteine hydrolase from Thermotoga maritima: Properties and its application on S-adenosylhomocysteine production with enzymatic cofactor regeneration

Paper ID Volume ID Publish Year Pages File Format Full-Text
17002 42630 2014 5 PDF Available
Title
A thermostable S-adenosylhomocysteine hydrolase from Thermotoga maritima: Properties and its application on S-adenosylhomocysteine production with enzymatic cofactor regeneration
Abstract

•T. maritima SAHase has an activity over 15-fold higher than that previously reported.•T. maritima LDH efficiently regenerated NAD at elevated temperatures.•A novel method for enzymatic production of S-adenosylhomocysteine was demonstrated.

S-adenosylhomocysteine (SAH) is an effective sedative, a good sleep modulator, and a new anticonvulsant. SAH can be synthesized from adenosine and homocysteine by using microbial S-adenosylhomocysteine hydrolase (SAHase). The extremely thermostable SAHase and lactate dehydrogenase (LDH) from Thermotoga maritima were successfully overexpressed in Escherichia coli, and purified by heat treatments. The SAHase exhibited the highest activity at 85 °C and pH 8.0 with a specific activity of 6.2 U/mg when NAD concentration was 1 mM. However, optimal SAHase reaction conditions shifted to 100 °C and pH 11.2, and its specific activity increased to 36.8 U/mg after NAD concentration was raised to 8 mM. Biosynthesis of SAH at 85 °C largely increased the adenosine solubility which was a limiting factor for improving the titer of product. At 85 °C and pH 8.0, 24 μmol of SAH was obtained when 0.5 mg of SAHase was applied to a 10 ml reaction mixture. The SAH production was further increased to 153 μmol by adding LDH and pyruvate into the reaction mixture for NAD regeneration. Therefore, extremely thermostable enzymes SAHase and LDH from T. maritima form an efficient NAD consumption and regeneration system for SAH biosynthesis. This method has great potential for industrial-scale enzymatic production of SAH.

Keywords
S-adenosylhomocysteine; S-adenosylhomocysteine hydrolase; Lactate dehydrogenase; NAD regeneration; Thermotoga maritima
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A thermostable S-adenosylhomocysteine hydrolase from Thermotoga maritima: Properties and its application on S-adenosylhomocysteine production with enzymatic cofactor regeneration
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volumes 64–65, October 2014, Pages 33–37
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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Any Questions? feel free to contact us