+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

O-demetnylation of biochanin A and some other isoflavones and methylated estrogens by microsomal liver enzymes

, : O-demetnylation of biochanin A and some other isoflavones and methylated estrogens by microsomal liver enzymes. Ark Kemi 21(2): 97-121

An enzyme system in the liver of a number of animal species is described. This enzyme system catalyzes the O-demethylation of biochanin A, formononetin and some other methoxylated isoflavones and estrogens into the corresponding phenol compound and formaldehyde. Like the enzymes of various oxidative reactions concerned with e.g. hydroxylation of steroids and detoxification of drugs this enzyme system was found to be located in the microsomes and to require both the reduced pyridine nucleotides and oxygen. The relations between biochanin A demethylation and other microsomal oxidase reactions are discussed. Data are given concerning the rate of biochanin A demethylation in test systems including different inhibitors and competitive substrates. The biochanin A demethylating enzyme system was found to agree with other oxidative microsomal enzymes in a number of ways, but differed in some respects. Cyanide inhibited the biochanin A demethylation but stimulated the demethylation of other methoxylated compounds. Peroxidase, but not catalase, caused an inhibition of the enzymatic activity. Fe++ stimulated the reaction, and the enzyme system was sensitive to reagents known to react with metal-dependent enzymes. SH inhibitors, heavy metals, and Mn++ strongly inhibited the reaction. Some evidence was found for substrate specificity of the biochanin A demethylating enzyme system.


Other references

Simpson, D.; Fagerli, H.; Hellsten, S.; Knulst, J.C.; Westling, O., 2006: Comparison of modelled and monitored deposition fluxes of sulphur and nitrogen to ICP-forest sites in Europe. The EMEP MSC-W Eulerian chemical transport model, and its predictions of deposition of acidifying and eutrophying pollutants over Europe, play a key role in the development of emission control strategies for Europe. It is important that this model...

Bedrov, I.A.; Gekhman, B.I., 1974: Role of central and peripheral thermosensitive structures in the regulation of cold shivering. Fiziologicheskii Zhurnal SSSR Imeni I. M. Sechenova 60(9): 1382-1388

Nordfeldt, S., 1946: Digestibility trials with pigs. 1. The effect of fibre content on digestibility. Comparison of the digestive capacity of sows and growing bacon pigs. (Lantbrukshogsk. Husdjursforsoksanst. Meddel. No. 23). Digestibility trials were made using Edin's indicator method (see Abst. 2054, Vol. 15). Individual feedingstuffs such as barley, oats, maize, lucerne silage and sugar beet were tested. Further experiments were made with mixtures of barley and...

Sobel, J.D., 2003: Management of patients with recurrent vulvovaginal candidiasis. Recurrent vulvovaginal candidiasis (RVVC) is by no means uncommon and is a source of considerable physical discomfort in addition to serving as a major therapeutic challenge. The syndrome is multifactorial in aetiology and hence management strateg...

House, T.; Keeling, M.J., 2008: Household structure and infectious disease transmission. One of the central tenets of modern infectious disease epidemiology is that an understanding of heterogeneities, both in host demography and transmission, allows control to be efficiently optimized. Due to the strong interactions present, househol...

Holloway Ralph L., 1985: The past, present and future significance of the lunate sulcus in early hominid evolution. Pages 47-62 1985

Geya, Y.; Kimura, T.; Fujisaki, H.; Terada, Y.; Kose, K.; Haishi, T.; Gemma, H.; Sekozawa, Y., 2013: Longitudinal NMR parameter measurements of Japanese pear fruit during the growing process using a mobile magnetic resonance imaging system. Longitudinal nuclear magnetic resonance (NMR) parameter measurements of Japanese pear fruit (Pyrus pyrifolia Nakai, Kosui) were performed using an electrically mobile magnetic resonance imaging (MRI) system with a 0.2 T and 16 cm gap permanent mag...

Friston, K.J., 1996: Theoretical neurobiology and schizophrenia. This chapter addresses the idea that schizophrenia is a 'disconnection syndrome' from a theoretical and computational perspective. The distinction between anatomical and functional connectivity is reviewed and used as a framework to intr...

Page S.T.; Elwood P.C., 1991: Genetic structure of the placental human folate receptor hfr gene and related genes. Proceedings of the American Association for Cancer Research Annual Meeting 32: 281

McLaughlin, C.W.; Coe, J.D., 1973: Cancer of the breast: an analysis of the 222 non-survivors in our personal series. Annals of Surgery 177(5): 620-625