Enzymatic modulation by Astaxanthin. In vitro evaluation of Astaxanthin interactions with vitamin A and prostaglandin pathway enzymes

Abstract

Astaxanthin, a marine-derived carotenoid, is recognized for its potent antioxidant and anti-inflammatory properties, however the molecular mechanisms behind its biological effects remain poorly defined. This thesis investigates the interactions between astaxanthin and selected protein targets, prostaglandin-H2 D-isomerase, beta-carotene 15,15’-dioxygenase, apolipoprotein D and apolipoprotein M, with an emphasis on potential enzymatic modulation. These proteins are involved in critical physiological processes, including prostaglandin metabolism, vitamin A conversion, and lipid transport, which are all relevant to redox homeostasis and inflammation. The study is framed within the broader context of a novel prodrug of astaxanthin, BPH-555, that Axelyf ehf. has developed to have increased bioavailability. By using astaxanthin itself as a model compound, this work contributes to the limited but growing body of research on how carotenoids modulate protein function and their connection to signaling pathways, including Nrf2 activation and NF-κB inhibition. Through this investigation, optimal conditions were identified for efficient SUMO tag cleavage for the selected protein targets, and a strategy was proposed to enhance the expression of proteins that are typically difficult to express. Additionally, insights were gained into the design of activity assays for enzymes such as prostaglandin-H2 D-isomerase and beta-carotene 15,15’-dioxygenase, by optimizing detergent and organic solvent conditions to support enzymatic function and substrate solubility.