Activating Compound | Comment | Organism | Structure |
---|---|---|---|
O2 | the DELTA1-dehydrogenation of 3-keto-4-en-steroid with KstD, purified from Nocardia corallina, is stimulated by molecular oxygen with stoichiometric production of hydrogen peroxide and 3-keto-1,4-diene-steroid | Gordonia rubripertincta |
Cloned (Comment) | Organism |
---|---|
gene acmB, recombinant expression in Escherichia coli | Sterolibacterium denitrificans |
gene kstD3, cloning and expression as a soluble protein in Escherichia coli | Gordonia neofelifaecis |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-androstene-3,17-dione + acceptor | Gordonia rubripertincta | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Rhodococcus erythropolis | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Rhodococcus ruber | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Sterolibacterium denitrificans | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Mycolicibacterium smegmatis | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Mycobacterium tuberculosis | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Gordonia neofelifaecis | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Rhodococcus erythropolis SQ1 | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Mycolicibacterium smegmatis ATCC 700084 | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Mycobacterium tuberculosis H37Rv | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Gordonia neofelifaecis NRRL B-59395 | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | Mycolicibacterium smegmatis mc(2)155 | - |
1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Gordonia rubripertincta | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Rhodococcus erythropolis | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Rhodococcus ruber | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Sterolibacterium denitrificans | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Mycolicibacterium smegmatis | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Mycobacterium tuberculosis | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Gordonia neofelifaecis | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Rhodococcus erythropolis SQ1 | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Mycolicibacterium smegmatis ATCC 700084 | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Mycobacterium tuberculosis H37Rv | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Gordonia neofelifaecis NRRL B-59395 | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | Mycolicibacterium smegmatis mc(2)155 | - |
a 3-oxo-delta1-steroid + reduced acceptor | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Gordonia neofelifaecis | - |
five KstD isozymes | - |
Gordonia neofelifaecis NRRL B-59395 | - |
five KstD isozymes | - |
Gordonia rubripertincta | - |
- |
- |
Mycobacterium tuberculosis | P71864 | a single enzyme | - |
Mycobacterium tuberculosis H37Rv | P71864 | a single enzyme | - |
Mycolicibacterium smegmatis | A0R4S9 | 6 KstD isozymes | - |
Mycolicibacterium smegmatis ATCC 700084 | A0R4S9 | 6 KstD isozymes | - |
Mycolicibacterium smegmatis mc(2)155 | A0R4S9 | 6 KstD isozymes | - |
Rhodococcus erythropolis | Q9RA02 | 3 KstD isozymes | - |
Rhodococcus erythropolis SQ1 | Q9RA02 | 3 KstD isozymes | - |
Rhodococcus ruber | C6GCU2 | three KstD isozymes | - |
Rhodococcus ruber | I0B6I6 | three KstD isozymes | - |
Rhodococcus ruber | I0B6J0 | three KstD isozymes | - |
Sterolibacterium denitrificans | A9XWD7 | a single enzyme | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
, 4,9(11)-androstadiene-3,17-dione + acceptor | - |
Gordonia neofelifaecis | ? + reduced acceptor | - |
? | |
, 4,9(11)-androstadiene-3,17-dione + acceptor | - |
Gordonia neofelifaecis NRRL B-59395 | ? + reduced acceptor | - |
? | |
16alpha,17alpha-epoxyprogesterone + acceptor | - |
Gordonia neofelifaecis | ? + reduced acceptor | - |
? | |
16alpha,17alpha-epoxyprogesterone + acceptor | - |
Gordonia neofelifaecis NRRL B-59395 | ? + reduced acceptor | - |
? | |
25-hydroxycholest-4-en-3-one + acceptor | - |
Sterolibacterium denitrificans | ? + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Gordonia rubripertincta | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Rhodococcus erythropolis | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Rhodococcus ruber | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Sterolibacterium denitrificans | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Mycolicibacterium smegmatis | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Mycobacterium tuberculosis | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Gordonia neofelifaecis | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Rhodococcus erythropolis SQ1 | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Mycolicibacterium smegmatis ATCC 700084 | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Mycobacterium tuberculosis H37Rv | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Gordonia neofelifaecis NRRL B-59395 | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-androstene-3,17-dione + acceptor | - |
Mycolicibacterium smegmatis mc(2)155 | 1,4-androstadiene-3,17-dione + reduced acceptor | - |
? | |
4-cholesten-3-one + acceptor | - |
Sterolibacterium denitrificans | ? + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Gordonia rubripertincta | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Rhodococcus erythropolis | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Rhodococcus ruber | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Sterolibacterium denitrificans | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Mycolicibacterium smegmatis | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Mycobacterium tuberculosis | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Gordonia neofelifaecis | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Rhodococcus erythropolis SQ1 | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Mycolicibacterium smegmatis ATCC 700084 | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Mycobacterium tuberculosis H37Rv | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Gordonia neofelifaecis NRRL B-59395 | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
a 3-oxosteroid + acceptor | - |
Mycolicibacterium smegmatis mc(2)155 | a 3-oxo-delta1-steroid + reduced acceptor | - |
? | |
additional information | KstD3 is active on a broad spectrum of substrates, comprising AD, progesterone, 4,9(11)-androstadiene-3,17-dione and 16alpha,17alpha-epoxyprogesterone. As usually the case with KstDs, the recombinant dehydrogenase is active neither with 3beta-/3alpha-hydroxysteroid nor with 3-ketosteroid containing a bulky C17-side chain, like 4-cholestene-3-one | Gordonia neofelifaecis | ? | - |
- |
|
additional information | the purified KstD catalyzes hydrogen transfer from 3-keto-4-ene-steroid (donor) into 3-keto-1,4-diene-steroid (acceptor), e.g. progesterone to 1,4-androstadiene-3,17-dione (ADD). The transhydrogenation reaction reaches equilibrium, and obeys to a typical ping-pong mechanism in which the donor is the first substrate, while the acceptor is the second. The transhydrogenation turnover number is of the same magnitude as that of the C1,2-dehydrogenation | Gordonia rubripertincta | ? | - |
- |
|
additional information | the recombinant enzyme is active with various 3-ketosteroids, including exceptionally the bulky side chain-containing steroids, 4-cholesten-3-one and 25-hydroxycholest-4-en-3-one | Sterolibacterium denitrificans | ? | - |
- |
|
additional information | KstD3 is active on a broad spectrum of substrates, comprising AD, progesterone, 4,9(11)-androstadiene-3,17-dione and 16alpha,17alpha-epoxyprogesterone. As usually the case with KstDs, the recombinant dehydrogenase is active neither with 3beta-/3alpha-hydroxysteroid nor with 3-ketosteroid containing a bulky C17-side chain, like 4-cholestene-3-one | Gordonia neofelifaecis NRRL B-59395 | ? | - |
- |
|
progesterone + acceptor | - |
Gordonia neofelifaecis | ? + reduced acceptor | - |
? |
Subunits | Comment | Organism |
---|---|---|
? | x * 62000, recombinant enzyme, SDS-PAGE | Sterolibacterium denitrificans |
? | x * 57000, recombinant KstD3, SDS-PAGE | Gordonia neofelifaecis |
Synonyms | Comment | Organism |
---|---|---|
3-ketosteroid delta1-dehydrogenase | - |
Gordonia rubripertincta |
3-ketosteroid delta1-dehydrogenase | - |
Rhodococcus erythropolis |
3-ketosteroid delta1-dehydrogenase | - |
Rhodococcus ruber |
3-ketosteroid delta1-dehydrogenase | - |
Sterolibacterium denitrificans |
3-ketosteroid delta1-dehydrogenase | - |
Mycolicibacterium smegmatis |
3-ketosteroid delta1-dehydrogenase | - |
Mycobacterium tuberculosis |
3-ketosteroid delta1-dehydrogenase | - |
Gordonia neofelifaecis |
AcmB | - |
Sterolibacterium denitrificans |
KstD | - |
Gordonia rubripertincta |
KstD | - |
Rhodococcus erythropolis |
KstD | - |
Rhodococcus ruber |
KstD | - |
Sterolibacterium denitrificans |
KstD | - |
Mycolicibacterium smegmatis |
KstD | - |
Mycobacterium tuberculosis |
KstD | - |
Gordonia neofelifaecis |
KSTD1 | - |
Rhodococcus ruber |
KSTD2 | - |
Rhodococcus ruber |
KSTD3 | - |
Rhodococcus ruber |
Rv3537 | - |
Mycobacterium tuberculosis |
Rv3537 | - |
Gordonia neofelifaecis |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8.4 | - |
transhydrogenation reaction | Gordonia rubripertincta |
8.5 | 10 | DELTA1-dehydrogenation of 3-keto-4-en-steroid | Gordonia rubripertincta |
10 | - |
substrate C1,2-dehydrogenation, in presence of phenazine methosulfate (PMS) | Gordonia rubripertincta |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
FAD | - |
Sterolibacterium denitrificans | |
phenazine methosulfate | PMS | Gordonia rubripertincta |
Organism | Comment | Expression |
---|---|---|
Rhodococcus erythropolis | the enzyme is induced during the bacterial growth on 17alpha-methyl-testosterone | up |
General Information | Comment | Organism |
---|---|---|
evolution | the genome of Rhodocccus ruber Chol-4 contains three genes that encode for 3-ketosteroid DELTA1-dehydrogenases: KstD1, KstD2 and KstD3. Their gene nucleotide sequences are similar to reciprocal homologues in other rhodococci. Physiological studies on strain Cho-4 and its kstD-deleted mutants demonstrate that the three dehydrogenases are involved in the catabolism of cholesterol at different degrees depending on catabolic intermediates. These KstDs are distinguished by their substrate profiles comprising C-19 and C-22 3-ketosteroids. Particularly, KstD3 has a preference for 5alpha-3-oxosteroids | Rhodococcus ruber |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration. The DELTA1-dehydrogenation of 3-keto-4-en-steroid with KstD, purified from Nocardia corallina, is stimulated by molecular oxygen with stoichiometric production of hydrogen peroxide and 3-keto-1,4-diene-steroid. In addition, the purified KstD catalyzes hydrogen transfer from 3-keto-4-ene-steroid (donor) into 3-keto-1,4-dienesteroid (acceptor), e.g. progesterone to 1,4-androstadiene-3,17-dione (ADD). The purified KstD of N. corallina catalyzes efficiently the aromatization of A-ring of 19-nortestosterone and 19-norandrostenedione to produce respectively beta-estradiol and estrone (phenolic compounds). Also, 19-hydroxytestosterone, 19-hydroxyandrostenedione, and 19-oxotestosterone are reported to be substrates for this KstD. Their dehydrogenation produces the respective phenolic steroids. This steroid A-ring aromatization with the isolated KstD is similar to an earlier bioconversion, carried out using microbial cultures on 19-hydroxy-4-stene-3-one. The process of this bioconversion consists of the 19-hydroxystenone side chain cleavage first and second, the A-ring aromatization of the steroid derivative, producing beta-estradiol and/or estrone. Microbial 9alpha-hydroxylation does not occur in the process, due to the C19-hydroxyl group steric hindrance | Gordonia rubripertincta |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Rhodococcus erythropolis |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Rhodococcus ruber |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Sterolibacterium denitrificans |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Mycolicibacterium smegmatis |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Mycobacterium tuberculosis |
physiological function | aerobic degradation of the sterol tetracyclic nucleus by microorganisms comprises the catabolism of A/B-rings, followed by that of C/D-rings. B-ring rupture at the C9,10-position is a key step involving 3-ketosteroid DELTA1-dehydrogenase (KstD) and 3-ketosteroid 9alpha-hydroxylase (KstH). Their activities lead to the aromatization of C4,5-en-containing A-ring causing the rupture of B-ring. C4,5alpha-hydrogenated 3-ketosteroid can be produced by the growing microorganism containing a 5alpha-reductase. In this case, the microorganism synthesizes, in addition to KstD and KstH, a 3-ketosteroid DELTA4-(5alpha)-dehydrogenase (Kst4D) in order to produce the A-ring aromatization, and consequently B-ring rupture. KstD and Kst4D are FAD-dependent oxidoreductases. KstH is composed of a reductase and a monooxygenase. This last component is the catalytic unit, it contains a Rieske-[2Fe-2S] center with a non-heme mononuclear iron in the active site. The characterized KstDs are active on 3-ketosteroids containing a short C17-chain or devoid of this chain. C-4,5-hydrogenated 3-ketosteroids are substrates, only if they are of the 5alpha-configuration | Gordonia neofelifaecis |