Selection of strains, which were generated in this study and used for production of recombinant SH variants.

aSH variants: wt = wildtype SH, untagged; 1 = SH variant 1: four-subunit enzyme HoxFUYH with N-terminally StrepII-tagged HoxF; 2 = SH variant 2: six-subunit enzyme HoxFUYHI2 with N-terminally StrepII-tagged HoxI.bAll recombinant strains were generated with E. coli BL21Star™ (DE3) as the basic strain.cSpecific activities were determined in extracts from cells obtained in three independent ‘autoinduction’ batches under optimized growth conditions outlined in the methods section of the paper. Given values are arithmetic means of the triplicate measurements. Statistical values indicated (±) represent standard deviations. 1 Unit is defined as the H2-mediated reduction of 1 µmol NAD+per minute.

a. SH变体：wt为未标记的野生型（wildtype）SH；变体1为四亚基酶HoxFUYH，其HoxF亚基N端带有StrepII标签；变体2为六亚基酶HoxFUYHI2，其HoxI亚基N端带有StrepII标签。
b. 所有重组菌株均以大肠杆菌（E. coli）BL21Star™ (DE3)作为基础菌株构建得到。
c. 比酶活通过细胞裂解液测定，所用细胞取自3批独立的自诱导（autoinduction）培养物，培养条件遵循论文方法部分所述的优化方案。报告数值为三次重复测量的算术平均值，标注的(±)代表标准偏差。1个酶活单位定义为：每分钟内由H₂介导还原1 μmol NAD⁺所需的酶量。