Sandbox Reserved 895: Difference between revisions
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Using sequence homology, RPE65 belong to a family of proteins known as carotenoid cleavage oxygenase (CCO) enzymes. This class of enzymes often cleave β-carotene or apocarotenoids. However, what makes RPE65 unique form all the other enzymes in this family is that RPE65 catalyzes an isomerhydrolase reaction. Additionally, unlike the other enzymes in the CCO family, there is no obvious role for molecular oxygen in the RPE65 enzymology. All members of the CCO family contain four conserved histidine residues (His180, His241, His313 and His527) that bind to an ion (Fe2+) cofactor. <ref> DOI 19805034 </ref> <ref> DOI 10.1016/j.bbadis.2018.04.014 </ref> | Using sequence homology, RPE65 belong to a family of proteins known as carotenoid cleavage oxygenase (CCO) enzymes. This class of enzymes often cleave β-carotene or apocarotenoids. However, what makes RPE65 unique form all the other enzymes in this family is that RPE65 catalyzes an isomerhydrolase reaction. Additionally, unlike the other enzymes in the CCO family, there is no obvious role for molecular oxygen in the RPE65 enzymology. All members of the CCO family contain four conserved histidine residues (His180, His241, His313 and His527) that bind to an ion (Fe2+) cofactor. <ref> DOI 19805034 </ref> <ref> DOI 10.1016/j.bbadis.2018.04.014 </ref> | ||
RPE65 can exist as both soluble and membrane bound forms which can undergo post-translational modifications (PTMs). At cystine residues Cys231, Cys239 and Cys330 the enzyme can be S-palmitoylated. S-palmitoylation of RPE65 was speculated to increase the ratio of membrane-bound to soluble RPE65 which can increase the enzymatic activity. <ref> DOI 15186777 </ref> However other studies have challenged this hypothesis and as such palmitoylation of RPE65 require further research to determine the activity. <ref> DOI 17504753 </ref> | |||
= References = | = References = | ||
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