The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Toshio Okano - One of the best experts on this subject based on the ideXlab platform.
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Measurement and characterization of C-3 Epimerization activity toward vitamin D3.
Archives of biochemistry and biophysics, 2005Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Kuniyo Inouye, Noboru Kubodera, G. Satyanarayana Reddy, Toshio OkanoAbstract:Recently, Epimerization of the hydroxyl group at C-3 has been identified as a unique metabolic pathway of vitamin D compounds. We measured C-3 Epimerization activity in subcellular fractions prepared from cultured cells and investigated the basic properties of the enzyme responsible for the Epimerization. C-3 Epimerization activity was detected using a NADPH-generating system containing glucose-6-phosphate, NADP, glucose-6-phosphate dehydrogenase, and Mg(2+). The highest level of activity was observed in a microsomal fraction prepared from rat osteoblastic UMR-106 cells but activity was also observed in microsomal fractions prepared from MG-63, Caco-2, Hep G2, and HUH-7 cells. In terms of maximum velocity (V(max)) and the Michaelis constant (K(m)), 25-hydroxyvitamin D(3) [25(OH)D(3)] exhibited the highest specificity for the Epimerization at C-3 among 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], 25(OH)D(3), 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], and 22-oxacalcitriol (OCT). The Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha-->beta)hydroxysteroid epimerase (HSE) catalyzed the Epimerization in vitro. Based on these results, the enzyme(s) responsible for the Epimerization of vitamin D(3) at C-3 are thought to be located in microsomes and different from cytochrome P450 and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of Steroid Biochemistry and Molecular Biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:Abstract It is well documented that Vitamin D 3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D 3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1α,25-Dihydroxyvitamin D 3 [1α,25(OH) 2 D 3 ], 25-hydroxyvitamin D 3 [25(OH)D 3 ] and 24,25-dihydroxyvitamin D 3 [24,25(OH) 2 D 3 ] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK 1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity ( V max ) and Michaelis constant ( K m ) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D 3 exhibited the highest specificity for the C-3 Epimerization among 1α,25(OH) 2 D 3 , 25(OH)D 3 and 24,25(OH) 2 D 3 . C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3( α → β )−hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D 3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of steroid biochemistry and molecular biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:It is well documented that Vitamin D3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1alpha,25-Dihydroxyvitamin D3 [1alpha,25(OH)2D3], 25-hydroxyvitamin D3 [25(OH)D3] and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity (Vmax) and Michaelis constant (Km) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D3 exhibited the highest specificity for the C-3 Epimerization among 1alpha,25(OH)2D3, 25(OH)D3 and 24,25(OH)2D3. C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha --> beta) -hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
Maya Kamao - One of the best experts on this subject based on the ideXlab platform.
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Measurement and characterization of C-3 Epimerization activity toward vitamin D3.
Archives of biochemistry and biophysics, 2005Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Kuniyo Inouye, Noboru Kubodera, G. Satyanarayana Reddy, Toshio OkanoAbstract:Recently, Epimerization of the hydroxyl group at C-3 has been identified as a unique metabolic pathway of vitamin D compounds. We measured C-3 Epimerization activity in subcellular fractions prepared from cultured cells and investigated the basic properties of the enzyme responsible for the Epimerization. C-3 Epimerization activity was detected using a NADPH-generating system containing glucose-6-phosphate, NADP, glucose-6-phosphate dehydrogenase, and Mg(2+). The highest level of activity was observed in a microsomal fraction prepared from rat osteoblastic UMR-106 cells but activity was also observed in microsomal fractions prepared from MG-63, Caco-2, Hep G2, and HUH-7 cells. In terms of maximum velocity (V(max)) and the Michaelis constant (K(m)), 25-hydroxyvitamin D(3) [25(OH)D(3)] exhibited the highest specificity for the Epimerization at C-3 among 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], 25(OH)D(3), 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], and 22-oxacalcitriol (OCT). The Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha-->beta)hydroxysteroid epimerase (HSE) catalyzed the Epimerization in vitro. Based on these results, the enzyme(s) responsible for the Epimerization of vitamin D(3) at C-3 are thought to be located in microsomes and different from cytochrome P450 and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of Steroid Biochemistry and Molecular Biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:Abstract It is well documented that Vitamin D 3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D 3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1α,25-Dihydroxyvitamin D 3 [1α,25(OH) 2 D 3 ], 25-hydroxyvitamin D 3 [25(OH)D 3 ] and 24,25-dihydroxyvitamin D 3 [24,25(OH) 2 D 3 ] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK 1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity ( V max ) and Michaelis constant ( K m ) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D 3 exhibited the highest specificity for the C-3 Epimerization among 1α,25(OH) 2 D 3 , 25(OH)D 3 and 24,25(OH) 2 D 3 . C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3( α → β )−hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D 3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of steroid biochemistry and molecular biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:It is well documented that Vitamin D3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1alpha,25-Dihydroxyvitamin D3 [1alpha,25(OH)2D3], 25-hydroxyvitamin D3 [25(OH)D3] and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity (Vmax) and Michaelis constant (Km) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D3 exhibited the highest specificity for the C-3 Epimerization among 1alpha,25(OH)2D3, 25(OH)D3 and 24,25(OH)2D3. C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha --> beta) -hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
Matthew D Shair - One of the best experts on this subject based on the ideXlab platform.
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synthesis of the n tert butyloxycarbonyl o triisopropylsilyl d pyrrolosamine glycal of lomaiviticin a b via Epimerization of l threonine
Tetrahedron Letters, 2010Co-Authors: William J Morris, Matthew D ShairAbstract:An efficient synthesis of the N-(tert-butyloxycarbonyl)-O-triisopropylsilyl-D-pyrrolosamine glycal of lomaiviticin A (1) and lomaiviticin B (2) is described. The synthesis is highlighted by the Epimerization of the L-threonine-derived oxazolidine 10 to oxazolidine 11. This key Epimerization reaction, which serves to establish the correct relative configuration of the carbohydrate unit, was made possible only after conformational analysis indicated that substituted oxazolidines may adopt conformations that preclude enolization.
Noboru Kubodera - One of the best experts on this subject based on the ideXlab platform.
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Measurement and characterization of C-3 Epimerization activity toward vitamin D3.
Archives of biochemistry and biophysics, 2005Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Kuniyo Inouye, Noboru Kubodera, G. Satyanarayana Reddy, Toshio OkanoAbstract:Recently, Epimerization of the hydroxyl group at C-3 has been identified as a unique metabolic pathway of vitamin D compounds. We measured C-3 Epimerization activity in subcellular fractions prepared from cultured cells and investigated the basic properties of the enzyme responsible for the Epimerization. C-3 Epimerization activity was detected using a NADPH-generating system containing glucose-6-phosphate, NADP, glucose-6-phosphate dehydrogenase, and Mg(2+). The highest level of activity was observed in a microsomal fraction prepared from rat osteoblastic UMR-106 cells but activity was also observed in microsomal fractions prepared from MG-63, Caco-2, Hep G2, and HUH-7 cells. In terms of maximum velocity (V(max)) and the Michaelis constant (K(m)), 25-hydroxyvitamin D(3) [25(OH)D(3)] exhibited the highest specificity for the Epimerization at C-3 among 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], 25(OH)D(3), 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], and 22-oxacalcitriol (OCT). The Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha-->beta)hydroxysteroid epimerase (HSE) catalyzed the Epimerization in vitro. Based on these results, the enzyme(s) responsible for the Epimerization of vitamin D(3) at C-3 are thought to be located in microsomes and different from cytochrome P450 and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of Steroid Biochemistry and Molecular Biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:Abstract It is well documented that Vitamin D 3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D 3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1α,25-Dihydroxyvitamin D 3 [1α,25(OH) 2 D 3 ], 25-hydroxyvitamin D 3 [25(OH)D 3 ] and 24,25-dihydroxyvitamin D 3 [24,25(OH) 2 D 3 ] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK 1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity ( V max ) and Michaelis constant ( K m ) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D 3 exhibited the highest specificity for the C-3 Epimerization among 1α,25(OH) 2 D 3 , 25(OH)D 3 and 24,25(OH) 2 D 3 . C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3( α → β )−hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D 3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of steroid biochemistry and molecular biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:It is well documented that Vitamin D3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1alpha,25-Dihydroxyvitamin D3 [1alpha,25(OH)2D3], 25-hydroxyvitamin D3 [25(OH)D3] and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity (Vmax) and Michaelis constant (Km) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D3 exhibited the highest specificity for the C-3 Epimerization among 1alpha,25(OH)2D3, 25(OH)D3 and 24,25(OH)2D3. C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha --> beta) -hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
Natsumi Sawada - One of the best experts on this subject based on the ideXlab platform.
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Measurement and characterization of C-3 Epimerization activity toward vitamin D3.
Archives of biochemistry and biophysics, 2005Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Kuniyo Inouye, Noboru Kubodera, G. Satyanarayana Reddy, Toshio OkanoAbstract:Recently, Epimerization of the hydroxyl group at C-3 has been identified as a unique metabolic pathway of vitamin D compounds. We measured C-3 Epimerization activity in subcellular fractions prepared from cultured cells and investigated the basic properties of the enzyme responsible for the Epimerization. C-3 Epimerization activity was detected using a NADPH-generating system containing glucose-6-phosphate, NADP, glucose-6-phosphate dehydrogenase, and Mg(2+). The highest level of activity was observed in a microsomal fraction prepared from rat osteoblastic UMR-106 cells but activity was also observed in microsomal fractions prepared from MG-63, Caco-2, Hep G2, and HUH-7 cells. In terms of maximum velocity (V(max)) and the Michaelis constant (K(m)), 25-hydroxyvitamin D(3) [25(OH)D(3)] exhibited the highest specificity for the Epimerization at C-3 among 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], 25(OH)D(3), 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], and 22-oxacalcitriol (OCT). The Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha-->beta)hydroxysteroid epimerase (HSE) catalyzed the Epimerization in vitro. Based on these results, the enzyme(s) responsible for the Epimerization of vitamin D(3) at C-3 are thought to be located in microsomes and different from cytochrome P450 and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of Steroid Biochemistry and Molecular Biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:Abstract It is well documented that Vitamin D 3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D 3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1α,25-Dihydroxyvitamin D 3 [1α,25(OH) 2 D 3 ], 25-hydroxyvitamin D 3 [25(OH)D 3 ] and 24,25-dihydroxyvitamin D 3 [24,25(OH) 2 D 3 ] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK 1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity ( V max ) and Michaelis constant ( K m ) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D 3 exhibited the highest specificity for the C-3 Epimerization among 1α,25(OH) 2 D 3 , 25(OH)D 3 and 24,25(OH) 2 D 3 . C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3( α → β )−hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D 3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.
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Cell specificity and properties of the C-3 Epimerization of Vitamin D3 metabolites.
The Journal of steroid biochemistry and molecular biology, 2004Co-Authors: Maya Kamao, Susumi Hatakeyama, Toshiyuki Sakaki, Natsumi Sawada, Noboru Kubodera, Syuichiro Tatematsu, Toshio OkanoAbstract:It is well documented that Vitamin D3 metabolites and synthetic analogs are metabolized to their epimers of the hydroxyl group at C-3 of the A-ring. We investigated the C-3 Epimerization of Vitamin D3 metabolites in various cultured cells and basic properties of the enzyme responsible for the C-3 Epimerization. 1alpha,25-Dihydroxyvitamin D3 [1alpha,25(OH)2D3], 25-hydroxyvitamin D3 [25(OH)D3] and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were metabolized to the respective C-3 epimers in UMR-106 (rat osteosarcoma), MG-63 (human osteosarcoma), Caco-2 (human colon adenocarcinoma), LLC-PK1 (porcine kidney) and HepG2 (human hepatoblastoma)] cells, although the differences existed in the amount of each C-3 epimer formed with different cell types. In terms of maximum velocity (Vmax) and Michaelis constant (Km) values for the C-3 Epimerization in microsome fraction of UMR-106 cells, 25(OH)D3 exhibited the highest specificity for the C-3 Epimerization among 1alpha,25(OH)2D3, 25(OH)D3 and 24,25(OH)2D3. C-3 Epimerization activity was not inhibited by various cytochrome P450 inhibitors and antiserum against NADPH cytochrome P450 reductase. Neither CYP24, CYP27A1, CYP27B1 nor 3(alpha --> beta) -hydroxysteroid epimerase (HSE) catalyzed the C-3 Epimerization in vitro. Based on these results, the enzyme responsible for the C-3 Epimerization of Vitamin D3 are thought to be different from already-known cytochrome P450-related Vitamin D metabolic enzymes and HSE.