Peroxisomal trifunctional enzyme possessing 2-enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and delta 3, delta 2-enoyl-CoA isomerase activities. Catalyzes two of the four reactions of the long chain fatty acids peroxisomal beta-oxidation pathway (PubMed:17442273, PubMed:24075987). Can also use branched-chain fatty acids such as 2-methyl-2E-butenoyl-CoA as a substrate, which is hydrated into (2S,3S)-3-hydroxy-2-methylbutanoyl-CoA (By similarity). Optimal isomerase for 2,5 double bonds into 3,5 form isomerization in a range of enoyl-CoA species. Also able to isomerize both 3-cis and 3-trans double bonds into the 2-trans form in a range of enoyl-CoA species (By similarity). With HSD17B4, catalyzes the hydration of trans-2-enoyl-CoA and the dehydrogenation of 3-hydroxyacyl-CoA, but with opposite chiral specificity (Probable). Regulates the amount of medium-chain dicarboxylic fatty acids which are essential regulators of all fatty acid oxidation pathways (PubMed:24075987). Also involved in the degradation of long-chain dicarboxylic acids through peroxisomal beta-oxidation (By similarity). a (3S)-3-hydroxyacyl-CoA = a (2E)-enoyl-CoA + H2O a 4-saturated-(3S)-3-hydroxyacyl-CoA = a (3E)-enoyl-CoA + H2O a (3Z)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA a (3E)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA a (3S)-3-hydroxyacyl-CoA + NAD(+) = a 3-oxoacyl-CoA + H(+) + NADH (2S,3S)-3-hydroxy-2-methylbutanoyl-CoA = (2E)-2-methylbut-2-enoyl-CoA + H2O (2E)-dodecenedioyl-CoA + H2O = (3S)-hydroxydodecanedioyl-CoA (3S)-hydroxydodecanedioyl-CoA + NAD(+) = 3-oxododecanedioyl-CoA + H(+) + NADH (2E)-octenedioyl-CoA + H2O = (3S)-hydroxyoctanedioyl-CoA (3S)-hydroxyoctanedioyl-CoA + NAD(+) = 3-oxooctanedioyl-CoA + H(+) + NADH (2E)-decenedioyl-CoA + H2O = (3S)-hydroxydecanedioyl-CoA (3S)-hydroxydecanedioyl-CoA + NAD(+) = 3-oxodecanedioyl-CoA + H(+) + NADH (2E)-tetradecenedioyl-CoA + H2O = (3S)-hydroxytetradecanedioyl-CoA (3S)-hydroxytetradecanedioyl-CoA + NAD(+) = 3-oxotetradecanedioyl-CoA + H(+) + NADH (3E,5Z)-tetradecadienoyl-CoA = (2E,5Z)-tetradecadienoyl-CoA (3E,5Z)-octadienoyl-CoA = (2E,5Z)-octadienoyl-CoA (3S)-hydroxydecanoyl-CoA + NAD(+) = 3-oxodecanoyl-CoA + H(+) + NADH (3E)-decenoyl-CoA = (2E)-decenoyl-CoA (3Z)-hexenoyl-CoA = (2E)-hexenoyl-CoA (3E)-hexenoyl-CoA = (2E)-hexenoyl-CoA (3S)-hydroxydecanoyl-CoA = (2E)-decenoyl-CoA + H2O (3S)-hydroxyhexanoyl-CoA = (2E)-hexenoyl-CoA + H2O (3S)-hydroxyhexadecanoyl-CoA + NAD(+) = 3-oxohexadecanoyl-CoA + H(+) + NADH (3S)-hydroxyhexadecanoyl-CoA = (2E)-hexadecenoyl-CoA + H2O (2E)-hexadecenedioyl-CoA + H2O = (3S)-hydroxyhexadecanedioyl-CoA (3S)-hydroxyhexadecanedioyl-CoA + NAD(+) = 3-oxohexadecanedioyl-CoA + H(+) + NADH Enzyme activity enhanced by acetylation. Lipid metabolism; fatty acid beta-oxidation. Monomer. Acetylated, leading to enhanced enzyme activity. Acetylation is enhanced by up to 80% after treatment either with trichostin A (TCA) or with nicotinamide (NAM) with highest increase on Lys-344. Acetylation and enzyme activity increased by about 1.5% on addition of fatty acids (By similarity). Mutant mice fed a normal chow are phenotypically indistinguishable from wild-types. Mutant mice fed coconut oil rapidly lose weight and most of them die within 3 weeks. They overaccumulate dicarboxylic fatty acids, which activate all fatty acid oxidation pathways and lead to liver inflammation, fibrosis, and death. In the N-terminal section; belongs to the enoyl-CoA hydratase/isomerase family. In the C-terminal section; belongs to the 3-hydroxyacyl-CoA dehydrogenase family.