The influence of anticoagulants on growth and vitamin K production of intestinal bacteria was stu... more The influence of anticoagulants on growth and vitamin K production of intestinal bacteria was studied. Bacteroides vulgatus and Escherichia coli were grown in vitro in the presence of increasing amounts of warfarin, phenprocoumon and acenocoumarol. It was found that growth of B. vulgatus was inhibited under anaerobic conditions whereas growth of E. coli under aerobic conditions was not inhibited. A specific inhibition of vitamin K biosynthesis was not observed in either case. It is concluded that therapeutic doses of anticoagulants are unlikely to affect growth or vitamin K production of intestinal bacteria.
Publisher Summary This chapter discusses degradation and incorporation procedures for the biosynt... more Publisher Summary This chapter discusses degradation and incorporation procedures for the biosynthesis of vitamin K 2 . In the biosynthesis of vitamin K one has to distinguish among three separate biosynthetic units, the aromatic nucleus, the isoprenoid side chain, and the nuclear methyl group. To conduct degradation experiments successfully, one has to be sure of an ultrapure sample that, in the case of vitamin K is particularly difficult to obtain, because contaminations with fatty acid esters, for instance, frequently occur. Vitamin K 2 is widely distributed between gram-positive and gramnegative bacteria. The average content of this naphthoquinone in bacteria is of the order of 1 micromole per gram dry weight. Six different species of bacteria with a known high content of vitamin K 2 have been tested for their ability to incorporate exogenously supplied shikimic acid- 14 C into vitamin K.
Annals of the New York Academy of Sciences, Dec 1, 1989
o-Succinylbenzoic acid (OSB) (i.e., 4-(2'-carboxyphenyl)-4-oxobutyrate) is a precursor of men... more o-Succinylbenzoic acid (OSB) (i.e., 4-(2'-carboxyphenyl)-4-oxobutyrate) is a precursor of menaquinones (i.e., vitamin K2) in bacteria and anthraquinones in plants and plant cell c ~ l t u r e s l ~ (FIG. 1) The aromatization leading to o-succinylbenzoic acid is likely to be a multistep reaction sequence. An intermediate in this sequence has been isolated and a structure p r ~ p o s e d . ~ Protein extracts from vitamin K-producing bacteria were shown to catalyze the formation of o-succinylbenzoic acid.'d One of the substrates for the enzyme system (OSB-synthase) was originally thought to be chorismic acid' but was later shown to be iso-chorismic a ~ i d . ~ . ~ . ~ In addition, a-ketoglutaric acid is a substrate of the OSB-synthase. a-Ketoglutaric acid is decarboxylated in the presence of thiamin pyrophosphate. The anion formed attacks iso-chorismic acid in a Michael-type reaction.' Evidence for the presence of an adduct formed from a-ketoglutaric acid and thiamin pyrophosphate was found in the following way: The bacterial OSB-synthase disintegrates during chromatography on Sephadex A-25 or Sephadex A-50.6 The decarboxylating subunit can be isolated. When incubated in the presence of a-ketoglutaric acid and thiamin pyrophosphate, the decarboxylating subunit catalyzcs the formation of CO, and two products which are likely to be adducts of thiamin pyrophosphate and a-ketoghtarate or succinic semialdehyde, respectively.6 The reaction mechanism of this decarboxylating subunit is therefore very likely identical to that of the decarboxylating subunit of the a-ketoglutarate dehydrogenase complex. Both the a-ketoglutarate dehydrogenase complex and the OSB-synthase, however, are distinct and separable catalytic entities.' The OSB synthase was not only detected in enzyme extracts of bacteria producing vitamin K but also in enzyme preparations obtained from anthraquinone-producing cell suspension cultures of Galium mollugo, Galium verum, and Galium uliginosum (Rubiaceae). Thus, menaquinones as well as anthraquinones are ultimately derived from a-ketoglutaric and iso-chorismic acid via o-succinylbenzoic acid.
. Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an a... more . Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an anthraquinone-producing cell-suspension culture of Galium mollugo L. Although attempts to stabilize the labile enzyme met with little success, a substantial increase in enzyme activity was observed in the presence of glycine betaine (500 mM). Column chromatography on solid supports other than diethylaminoethyl (DEAE)-Sephacel, Phenylsepharose Cl-4B or Cibacron Blue 3G-A
The influence of anticoagulants on growth and vitamin K production of intestinal bacteria was stu... more The influence of anticoagulants on growth and vitamin K production of intestinal bacteria was studied. Bacteroides vulgatus and Escherichia coli were grown in vitro in the presence of increasing amounts of warfarin, phenprocoumon and acenocoumarol. It was found that growth of B. vulgatus was inhibited under anaerobic conditions whereas growth of E. coli under aerobic conditions was not inhibited. A specific inhibition of vitamin K biosynthesis was not observed in either case. It is concluded that therapeutic doses of anticoagulants are unlikely to affect growth or vitamin K production of intestinal bacteria.
Publisher Summary This chapter discusses degradation and incorporation procedures for the biosynt... more Publisher Summary This chapter discusses degradation and incorporation procedures for the biosynthesis of vitamin K 2 . In the biosynthesis of vitamin K one has to distinguish among three separate biosynthetic units, the aromatic nucleus, the isoprenoid side chain, and the nuclear methyl group. To conduct degradation experiments successfully, one has to be sure of an ultrapure sample that, in the case of vitamin K is particularly difficult to obtain, because contaminations with fatty acid esters, for instance, frequently occur. Vitamin K 2 is widely distributed between gram-positive and gramnegative bacteria. The average content of this naphthoquinone in bacteria is of the order of 1 micromole per gram dry weight. Six different species of bacteria with a known high content of vitamin K 2 have been tested for their ability to incorporate exogenously supplied shikimic acid- 14 C into vitamin K.
Annals of the New York Academy of Sciences, Dec 1, 1989
o-Succinylbenzoic acid (OSB) (i.e., 4-(2'-carboxyphenyl)-4-oxobutyrate) is a precursor of men... more o-Succinylbenzoic acid (OSB) (i.e., 4-(2'-carboxyphenyl)-4-oxobutyrate) is a precursor of menaquinones (i.e., vitamin K2) in bacteria and anthraquinones in plants and plant cell c ~ l t u r e s l ~ (FIG. 1) The aromatization leading to o-succinylbenzoic acid is likely to be a multistep reaction sequence. An intermediate in this sequence has been isolated and a structure p r ~ p o s e d . ~ Protein extracts from vitamin K-producing bacteria were shown to catalyze the formation of o-succinylbenzoic acid.'d One of the substrates for the enzyme system (OSB-synthase) was originally thought to be chorismic acid' but was later shown to be iso-chorismic a ~ i d . ~ . ~ . ~ In addition, a-ketoglutaric acid is a substrate of the OSB-synthase. a-Ketoglutaric acid is decarboxylated in the presence of thiamin pyrophosphate. The anion formed attacks iso-chorismic acid in a Michael-type reaction.' Evidence for the presence of an adduct formed from a-ketoglutaric acid and thiamin pyrophosphate was found in the following way: The bacterial OSB-synthase disintegrates during chromatography on Sephadex A-25 or Sephadex A-50.6 The decarboxylating subunit can be isolated. When incubated in the presence of a-ketoglutaric acid and thiamin pyrophosphate, the decarboxylating subunit catalyzcs the formation of CO, and two products which are likely to be adducts of thiamin pyrophosphate and a-ketoghtarate or succinic semialdehyde, respectively.6 The reaction mechanism of this decarboxylating subunit is therefore very likely identical to that of the decarboxylating subunit of the a-ketoglutarate dehydrogenase complex. Both the a-ketoglutarate dehydrogenase complex and the OSB-synthase, however, are distinct and separable catalytic entities.' The OSB synthase was not only detected in enzyme extracts of bacteria producing vitamin K but also in enzyme preparations obtained from anthraquinone-producing cell suspension cultures of Galium mollugo, Galium verum, and Galium uliginosum (Rubiaceae). Thus, menaquinones as well as anthraquinones are ultimately derived from a-ketoglutaric and iso-chorismic acid via o-succinylbenzoic acid.
. Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an a... more . Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an anthraquinone-producing cell-suspension culture of Galium mollugo L. Although attempts to stabilize the labile enzyme met with little success, a substantial increase in enzyme activity was observed in the presence of glycine betaine (500 mM). Column chromatography on solid supports other than diethylaminoethyl (DEAE)-Sephacel, Phenylsepharose Cl-4B or Cibacron Blue 3G-A
Uploads