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Highlights • Progesterone converted by the fungus Aspergillus sojae PTCC 5196 produced testololactone. • The production of testololactone indicated fungal Baeyer-Villiger monooxygenase (BVMO) activity. • Substrate-induced cultures have a decisive impact on the metabolism of progesterone. • Progesterone, a C-21 steroidal compound, induced 17β-acetyl side chain cleavage. • Androstenedione, testosterone, and DHEA, C-19 steroidal substances, induced ring-D oxidation. Abstract Microbial transformations are capable of producing steroid substances difficult to synthesize by chemical methods. Strains belonging to the genus Aspergillus are effective facilitators of microbial biotransformations due to their enzymatic diversity. In this study, the biotransformation of progesterone by the fungus Aspergillus sojae (A. sojae) PTCC 5196 was examined. Analysis of the bioconversion process revealed that progesterone was converted to testololactone through a three-step pathway (17β-acetyl side chain cleavage, 17β-hydroxyl oxidation, and oxygenative lactonization of 17-ketone), indicating the presence of Baeyer-Villiger monooxygenase (BVMO) activity in the fungal strain. GC analysis confirmed the production of testololactone with a yield of 99% in 24 h. Faster testololactone production was induced in the presence of both C-21 (progesterone) and C-19 (androstenedione, testosterone, and dehydroepiandrosterone [DHEA]) steroid substances. Due to the high biotransformation rate observed in the present study, A. sojae may be a novel and promising candidate in the production of testololactone. [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify the C11-oxy C 19 and C11-oxy C 21 steroids in male and female neonate plasma. At birth, the most abundant C11-oxy steroids detected in neonatal plasma were 11β-hydroxyandrostenedione, ∼13 nM, and 11-ketoprogesterone, ∼23 nM. C11-oxy C 19 steroids were higher than C 19 steroids in neonatal plasma, 22.2 nM vs 5.4 nM. The inclusion of C11-oxy C 19 and C 21 steroid reference ranges in routine steroid analyses will assist the characterization of disorders associated with impaired steroidogenic enzyme expression and the identification of potential biomarkers. [ABSTRACT FROM AUTHOR]

Glutathione transferases (GSTs) comprise a superfamily of enzymes prominently involved in detoxication by making toxic electrophiles more polar and therefore more easily excretable. However some GSTs have developed alternative functions. Thus, a member of the Alpha class GSTs in pig and human tissues is involved in steroid hormone biosynthesis, catalyzing the obligatory double-bond isomerization of Δ 5 -androstene-3,17-dione to Δ 4 -androstene-3,17-dione and of Δ 5 -pregnene-3,20-dione to Δ 4 -pregnene-3,20-dione on the biosynthetic pathways to testosterone and progesterone. The human GST A3-3 is the most efficient steroid double-bond isomerase known so far in mammals. The current work extends discoveries of GST enzymes that act in the steroidogenic pathways in large mammals. The mRNA encoding the steroid isomerase GST A3-3 was cloned from testis of the horse ( Equus ferus caballus). The concentrations of GSTA3 mRNA were highest in hormone-producing organs such as ovary, testis and adrenal gland. EcaGST A3-3 produced in E. coli has been characterized and shown to have highly efficient steroid double-bond isomerase activity, exceeding its activities with conventional GST substrates. The enzyme now ranks as one of the most efficient steroid isomerases known in mammals and approaches the activity of the bacterial ketosteroid isomerase, one of the most efficient enzymes of all categories known today. The high efficiency and the tissue distribution of EcaGST A3-3 support the view that the enzyme plays a physiologically significant role in the biosynthesis of steroid hormones. [ABSTRACT FROM AUTHOR]