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Hydroxysteroid dehydrogenase
About: Hydroxysteroid dehydrogenase is a research topic. Over the lifetime, 1087 publications have been published within this topic receiving 28468 citations. The topic is also known as: hydroxysteroid dehydrogenase.
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TL;DR: The basic for undertaking the present investigation was provided by results of preliminary experiments showing the presence of a nonreceptor protein, intensively binding 3H-estradiol, in the soluble fraction of rabbit liver, which possesses oxidoreductase activity relative to androgens and gestagens.
Abstract: One of the mechanisms of regional regulation of steroid hormone reception and metabolism may be reversible interaction of these hormones with specific intracellular nonreceptor proteins, or steromodulins [3, 5, 7]. This group of substances includes proteins similar or identical to blood transport proteins, and specialized, tissue-specific proteins of the special estrogen-binding protein (SEBP) type of rat liver [I, 12, 13]. The basic for undertaking the present investigation was provided by results of preliminary experiments showing the presence of a nonreceptor protein, intensively binding 3H-estradiol, in the soluble fraction of rabbit liver. It was found in the course of the work that this protein possesses oxidoreductase activity relative to androgens and gestagens.
TL;DR: In this article , a new and natively NADH-dependent 7β-HSDH from Roseococcus sp. was identified, which showed a high specific activity of 63.3 U mg−1protein toward 7-oxo-lithocholic acid, with a catalytic efficiency (kcat/KM) of 515 mM−1 s−1.
Abstract: 7β-Hydroxysteroid dehydrogenases (7β-HSDHs) play an important role in the enzymatic synthesis of ursodeoxycholic acid (UDCA), which is a value-added compound with a range of pharmacological activities. Since the cofactor NADH is much cheaper than NADPH, the production of UDCA using an NADH-dependent 7β-HSDH has better prospects than that using an NADPH-dependent 7β-HSDH. However, a major bottleneck in UDCA biosynthesis is the poor catalytic activity of the current NADH-dependent 7β-HSDHs. In this work, a new and natively NADH-dependent Rs7β-HSDH from Roseococcus sp. was identified, which showed a high specific activity of 63.3 U mg−1protein toward 7-oxo-lithocholic acid, with a catalytic efficiency (kcat/KM) of 515 mM–1 s–1. In a preparative biotransformation (100-mL scale) using Rs7β-HSDH and an NAD+-dependent 7α-HSDH, with O2/NOX and HCOO−/FDH systems for the regeneration of cofactors (NAD+ and NADH), 25 mM chenodeoxycholic acid was completely converted to UDCA in one-pot two-step cascade, with an 80% isolated yield and a total turnover number (TTN) of 6586 for Rs7β-HSDH. The environmental factor (E-factor) of this process was 8.37 when water was excluded, much lower than those obtained from other processes reported so far, indicating a great potential of this Rs7β-HSDH for more sustainable and cleaner enzymatic production of UDCA.
TL;DR: In this article, the identification of three 20β-HSD type 2 genes in X. laevis and the functional characterization of the two homeologs from X. leaevis were presented.