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Proteins/UNIPROT:Q92506
Required for the solubility and assembly of the heterotetramer 3-ketoacyl-[acyl carrier protein] (ACP) reductase functional complex (KAR or KAR1) that forms part of the mitochondrial fatty acid synthase (mtFAS). Alpha-subunit of the KAR complex that acts as a scaffold protein required for the stability of carbonyl reductase type-4 (CBR4, beta-subunit of the KAR complex) and for its 3-ketoacyl-ACP reductase activity, thereby participating in mitochondrial fatty acid biosynthesis. Catalyzes the NAD-dependent conversion of (3R)-3-hydroxyacyl-CoA into 3-ketoacyl-CoA (3-oxoacyl-CoA) with no chain length preference; this enzymatic activity is not needed for the KAR function. Prefers (3R)-3-hydroxyacyl-CoA over (3S)-3-hydroxyacyl-CoA and displays enzymatic activity only in the presence of NAD(+). Cooperates with enoyl-CoA hydratase 1 in mitochondria, together they constitute an alternative route to the auxiliary enzyme pathways for the breakdown of Z-PUFA (cis polyunsaturated fatty acid) enoyl-esters (Probable). NAD-dependent 17-beta-hydroxysteroid dehydrogenase with highest activity towards estradiol (17beta-estradiol or E2). Has very low activity towards testosterone and dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one). Primarily an oxidative enzyme, it can switch to a reductive mode determined in the appropriate physiologic milieu and catalyze the reduction of estrone (E1) to form biologically active 17beta-estradiol..
Function from UniProtKB (Q92506), read 2026-09-23. CC BY 4.0.
Curated compounds routed: 1 · substrate of
1 compound
1 compound.
0 reported routes1 assembled route
130 statements
130 statements · 7 reference databases · Subject: HSD17B8 · Sources: Bgee, Hetionet, Human Protein Atlas, Human-GEM, Reactome, Rhea, WikiPathways
14 reactions
15 names
Resolves to: HSD17B8
Human-GEM MAR01098CC BY 4.0Reference data
MAM00747r+proton+NADPH(4-)MAM01087r+NADP(3-)
Catalysed by HSD17B14 or HSD3B7 or DHRS2 or HTATIP2 or RDH10 or MDH1B or RDH12 or CBR4 or CTBP1 or BDH2 or HSD11B1L or SDR9C7 and 12 more alternatives
Reaction pageReversibleBalancedEC 1.1.1.-endoplasmic reticulum
Human-GEM MAR01813CC BY 4.0Reference data
androst-4-ene-3,17-dione+proton+NADPH(4-)NADP(3-)+testosterone
Catalysed by HSD17B6 or HSD17B2 or HSD17B1 or HSD17B3 or HSD17B7 or AKR1C3 or HSD17B11 or HSD17B8
Reaction pageLeft to rightBalancedEC 1.1.1.62, 1.1.1.64cytosol
Human-GEM MAR01973CC BY 4.0Reference data
estrone+proton+NADPH(4-)17beta-estradiol+NADP(3-)
Catalysed by HSD17B6 or HSD17B2 or HSD17B1 or HSD17B7 or HSD17B12 or HSD17B11 or HSD17B8
Reaction pageReversibleBalancedEC 1.1.1.62cytosol
Human-GEM MAR02036CC BY 4.0Reference data
estrone+proton+NADPH(4-)17beta-estradiol+NADP(3-)
Catalysed by HSD17B6 or HSD17B2 or HSD17B1 or HSD17B7 or HSD17B12 or HSD17B11 or HSD17B8
Reaction pageReversibleBalancedEC 1.1.1.62endoplasmic reticulum
Human-GEM MAR02041CC BY 4.0Reference data
MAM01029c+proton+NADPH(4-)MAM01229c+NADP(3-)
Catalysed by HTATIP2 or MDH1B or RDH12 or CBR4 or CTBP1 or RDH13 or BDH2 or HSD11B1L or SDR9C7 or SDR16C5 or HSD11B2 or SDR42E2 and 10 more alternatives
Reaction pageReversibleBalancedEC 1.1.1.-cytosol
Human-GEM MAR06670CC BY 4.0Reference data
4-methyl-2-oxopentanoate+proton+NADH(2-)2-hydroxy-4-methylvaleric acid+NAD(+)
Catalysed by DHRS2 or HTATIP2 or MDH1B or CBR4 or CTBP1 or BDH2 or HSD11B1L or SDR9C7 or SDR16C5 or SDR42E2 or SDR42E1 or WWOX and 6 more alternatives
Reaction pageReversibleBalancedEC 1.1.1.-cytosol
Human-GEM MAR06925CC BY 4.0Reference data
androst-4-ene-3,17-dione+proton+NADH(2-)NAD(+)+testosterone
Catalysed by HSD17B6 or HSD17B2 or HSD17B8
Reaction pageLeft to rightBalancedEC 1.1.1.239endoplasmic reticulum
Human-GEM MAR07955CC BY 4.0Reference data
estrone+proton+NADH(2-)17beta-estradiol+NAD(+)
Catalysed by HSD17B6 or HSD17B2 or HSD17B1 or HSD17B7 or HSD17B12 or HSD17B11 or HSD17B8
Reaction pageLeft to rightBalancedEC 1.1.1.62, 1.1.1.64endoplasmic reticulum
Human-GEM MAR07968CC BY 4.0Reference data
MAM00799m+NADP(3-)proton+NADPH(4-)+MAM03168m
Catalysed by DHRS2 or HTATIP2 or MDH1B or RDH12 or CBR4 or CTBP1 or BDH2 or HSD11B1L or SDR9C7 or SDR42E2 or SDR42E1 or WWOX and 7 more alternatives
Reaction pageReversibleBalancedEC 1.1.1.-mitochondrial matrix
Human-GEM MAR09804CC BY 4.0Reference data
testosterone+NAD(1-)androst-4-ene-3,17-dione+NADH(2-)+hydron
Catalysed by HSD17B6 or AKR1C4 or HSD17B2 or AKR1C3 or HSD17B8 or HSD17B10
Reaction pageLeft to rightBalanced
Rhea RHEA:14929CC BY 4.0Reference data