The Effects of Cosolvent and Incubation Temperature on the Enantioselectivity of Aliphatic Ketone Reductions Catalyzed by Thermostable Secondary Alcohol Dehydrogenases

Abstract Abstract 4806 Introduction Pixantrone (PIX), an aza-anthracenedione, which has successfully completed a phase 3 trial (J Clin Oncol 2009; 27:15s, No. 8523) was designed to enhance clinical efficacy while significantly decreasing cardiotoxicity compared to doxorubicin (DOX) and mitoxantrone (MIT). Multidose administration, in animal models of equitoxic doses of PIX, MIT, and DOX, with or without prior therapy with DOX, resulted in minimal evidence for PIX cardiotoxicity compared with the severe histologic lesions seen with these other agents (Cavaletti et al: Investigational New Drugs 2007; 3:187-95). Both DOX and MIT contain a dihydroquinone structural element known to interact with iron. Additionally, DOX contains an aliphatic ketone which, once metabolized to the corresponding secondary alcohol metabolite doxorubicinol, is implicated in release of free iron and the chronic cardiotoxicity observed with DOX. In contrast, PIX has a nitrogen containing heterocycle which replaces the dihydroquinone, forming an aza-anthracenedione structure. PIX also does not contain an aliphatic ketone and cannot form metabolites analogous to doxorubicinol. Methods To validate the proposed mechanisms underlying the observed differences in cardiotoxicity, we used established spectrophotometric techniques to quantify iron:drug interactions that are thought to be mechanistic for chronic doxorubicin cardiotoxicity (Menna et al: Cardiovasc Toxicol 2007; 7:80–85). Results Adding increasing amounts of iron to drug solution, we observed that DOX and MIT underwent changes in visible range absorbance patterns, characteristic of drug:iron complex formation, confirming the expected 1:3 Fe(II)-drug ratio for both DOX and MIT. In contrast, no spectrophotometric changes were observed with iron added to PIX, clearly demonstrating that PIX does not bind iron. In vitro studies using H2C9 rat myocardial cells indicate that PIX (ID50 >50 μg/ml) is far less toxic than DOX (ID50= 1 μ/ml). Moreover, PIX does not induce significant reactive oxygen species (ROS) production in the H2C9 cells compared to DOX. Conclusion These results demonstrate that PIX does not bind iron and that its inability to bind iron and its reduced propensity to generate ROS may be the mechanism for reduced PIX cardiotoxicity in animal models compared to DOX or MIT. Disclosures: McKennon: Cell Therapeutics, Inc: Employment. Singer:Cell Therapeutics, Inc: Employment.

Download Full-text

Efficient 1-Hydroxy-2-Butanone Production from 1,2-Butanediol by Whole Cells of Engineered E. coli

Catalysts ◽

10.3390/catal11101184 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1184

Author(s):

Hui Lin ◽

Jiayin Xu ◽

Wenlian Sun ◽

Wujia Hu ◽

Huifang Gao ◽

...

Keyword(s):

Escherichia Coli ◽

Nadh Oxidase ◽

Secondary Alcohol ◽

Chiral Resolution ◽

Glycerol Dehydrogenase ◽

Alcohol Dehydrogenases ◽

Whole Cells ◽

E Coli ◽

Optimized Conditions ◽

Butanediol Dehydrogenase

1-Hydroxy-2-butanone (HB) is a key intermediate for anti-tuberculosis pharmaceutical ethambutol. Commercially available HB is primarily obtained by the oxidation of 1,2-butanediol (1,2-BD) using chemical catalysts. In present study, seven enzymes including diol dehydrogenases, secondary alcohol dehydrogenases and glycerol dehydrogenase were chosen to evaluate their abilities in the conversion of 1,2-BD to HB. The results showed that (2R, 3R)- and (2S, 3S)-butanediol dehydrogenase (BDH) from Serratia sp. T241 could efficiently transform (R)- and (S)-1,2-BD into HB respectively. Furthermore, two biocatalysts co-expressing (2R, 3R)-/(2S, 3S)-BDH, NADH oxidase and hemoglobin protein in Escherichia coli were developed to convert 1,2-BD mixture into HB, and the transformation conditions were optimized. Maximum HB yield of 341.35 and 188.80 mM could be achieved from 440 mM (R)-1,2-BD and 360 mM (S)-1,2-BD by E. coli (pET-rrbdh-nox-vgb) and E. coli (pET-ssbdh-nox-vgb) under the optimized conditions. In addition, two biocatalysts showed the ability in chiral resolution of 1,2-BD isomers, and 135.68 mM (S)-1,2-BD and 112.43 mM (R)-1,2-BD with the purity of 100 % could be obtained from 300 and 200 mM 1,2-BD mixture by E. coli (pET-rrbdh-nox-vgb) and E. coli (pET-ssbdh-nox-vgb), respectively. These results provided potential application for HB production from 1,2-BD mixture and chiral resolution of (R)-1,2-BD and (S)-1,2-BD.

Download Full-text

Histochemical localization of primary and secondary alcohol dehydrogenases in whole-body, freeze-dried sections of mice

The Histochemical Journal ◽

10.1007/bf01003849 ◽

1984 ◽

Vol 16 (9) ◽

pp. 931-940 ◽

Cited By ~ 5

Author(s):

Toru Egashira ◽

William J. Waddell

Keyword(s):

Secondary Alcohol ◽

Whole Body ◽

Histochemical Localization ◽

Alcohol Dehydrogenases ◽

Freeze Dried

Download Full-text

Histochemical localization of glycolytic enzymes, alcohol and secondary-alcohol dehydrogenases in the testes of buffaloes, goats and rams

The Journal of Agricultural Science ◽

10.1017/s0021859600037813 ◽

1983 ◽

Vol 101 (2) ◽

pp. 457-462 ◽

Cited By ~ 2

Author(s):

G. S. Bilaspuri ◽

S. S. Guraya

Keyword(s):

Lactate Dehydrogenase ◽

Alcohol Dehydrogenase ◽

Carbohydrate Metabolism ◽

Secondary Alcohol ◽

Seminiferous Tubules ◽

Interstitial Tissue ◽

Basic Pattern ◽

Alcohol Dehydrogenases ◽

Secondary Alcohol Dehydrogenase ◽

Species Specific

SUMMARYGlyceraldehyde-3-phosphate dehydrogenase (G-3-PDH), αglycerophosphate dehydrogenase (αGPDH), lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) and secondary-alcohol dehydrogenase (SADH) were histochemically located in the testes of buffaloes, goats and rams. Two forms of αGPDH were observed: (i) NAD-dependent or cytoplasmic αglycero-phosphate dehydrogenase (αGPDHC) and (ii) NAD-independent or mitochondrial αglycerophosphate dehydrogenase (α GPDHM). The basic pattern of distribution of the various enzymes was similar in the three species; species-specific variations were observed but cell-specific variations were more pronounced. The main activities of G-3-PDH and αGPDHM were observed in the seminiferous tubules; interstitial tissue showed moderate (G-3-PDH) and trace to weak (αGPDHM) activity. In contrast, αGPDHC activity was more marked in the interstitial tissue and less in the seminiferous tubules, especially in the mature germinal elements. LDH and ADH respectively showed strong and moderate activities in the interstitial tissue and seminiferous tubules. SADH was noticeable only in the interstitial tissue of buffalo. The activities of all enzymes other than αGPDHC increased during spermiogenesis. The physiological significance of the results is discussed in relation to the carbohydrate metabolism of the testis.

Download Full-text