Spacey Harry J, Healy Daniel, Kalapothakis Jason M D, Ma Junfeng, Sakuma Michiyo, Barran Perdita E, Heyes Derren J, Scrutton Nigel S
Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
ACS Catal. 2025 Mar 31;15(8):6088-6097. doi: 10.1021/acscatal.4c07757. eCollection 2025 Apr 18.
Fatty acid photodecarboxylase (FAP) is a FAD-containing enzyme that catalyzes the light-driven decarboxylation of medium-long chain fatty acids. Over recent years, the substrate scope of FAP has been broadened to improve its potential to catalyze a range of blue light-dependent industrially relevant reactions. However, photoinactivation constitutes a major hurdle for generalized applications. Previous studies have suggested that violet light may be a more suitable illumination wavelength for many of these applications. Here, we have investigated any possible enhancement in the catalytic activity of FAP upon illumination with violet light and utilized a spectrophotometric assay that detects the production of CO in real time to monitor the FAP reaction under different illumination conditions. We show that the activity of FAP at low intensities of violet light is approximately 6-fold higher than under identical illumination conditions with blue light. Moreover, the product yield increases further when the light is delivered in a pulsed manner, most likely as a result of lower levels of photoinactivation than is observed upon continuous illumination. More detailed spectrophotometric measurements have confirmed that FAP employs a similar catalytic cycle upon illumination with both violet and blue light. Rather, the enhancement in catalytic efficiency observed with violet light is attributable to higher populations of excited state FAD species that can proceed along a productive catalytic pathway. We suggest that pulses of low-intensity violet light provide an optimized route for FAP catalysis, highlighting the importance of illumination conditions in the expanding field of flavin-based photobiocatalysis.
脂肪酸光脱羧酶（FAP）是一种含黄素腺嘌呤二核苷酸（FAD）的酶，可催化中长链脂肪酸的光驱动脱羧反应。近年来，FAP的底物范围已得到拓宽，以提高其催化一系列蓝光依赖性工业相关反应的潜力。然而，光失活是其广泛应用的主要障碍。先前的研究表明，紫光可能是许多此类应用中更合适的照明波长。在此，我们研究了紫光照射下FAP催化活性的任何可能增强，并利用一种可实时检测CO生成的分光光度法来监测不同光照条件下的FAP反应。我们发现，在低强度紫光照射下，FAP的活性比在相同蓝光照射条件下高出约6倍。此外，当以脉冲方式提供光照时，产物产率会进一步提高，这很可能是由于光失活水平低于连续光照时的水平。更详细的分光光度测量证实，FAP在紫光和蓝光照射下采用相似的催化循环。相反，紫光观察到的催化效率提高归因于更多能够沿着有效催化途径进行的激发态FAD物种。我们认为，低强度紫光脉冲为FAP催化提供了一条优化途径，突出了光照条件在基于黄素的光生物催化不断扩展的领域中的重要性。
