Immunopurified 25-hydroxyvitamin D 1 alpha-hydroxylase and 1,25-dihydroxyvitamin D 24-hydroxylase are closely related but distinct enzymes.
نویسندگان
چکیده
منابع مشابه
Measurement of mammalian 25 - hydroxyvitamin D 3 24 R - and la - hydroxylase ( 1 , 25 - dihydroxyvitamin D 3 / 24 , 25 - dihydroxyvitamin D / kidney / calcium ) YOKO TANAKA AND
An in vitro assay of mammalian 25-hydroxyvitamin D3 laand 24R-hydroxylases in kidney has been developed. It had been suggested that 25-hydroxyvitamin D binding protein present in mammalian blood and tissues inhibits the enzyme activities in cell-free preparations by binding the substrate 25-hydroxyvitamin D3 more strongly than the hydroxylases bind it. This inhibitory effect is overcome by the ...
متن کاملRelative expression of 1,25-dihydroxyvitamin D3 receptor, vitamin D 1 alpha-hydroxylase, vitamin D 24-hydroxylase, and vitamin D 25-hydroxylase in endometriosis and gynecologic cancers.
The authors demonstrate expression of the vitamin D receptor (VDR) and its hydroxylases in the endometrium and ovaries of women with and without endometriosis and endometrial or ovarian cancer. Immunohistochemistry showed strong staining of the VDR in endometriosis and endometrial cancer, with the most intense staining in epithelial cells. The VDR mRNA was significantly increased in patients wi...
متن کاملKinetic behavior of 25-hydroxyvitamin D-1-hydroxylase and -24-hydroxylase in rat kidney mitochondria.
Although 25-hydroxyvitamin D (25-OHD)-l-hydroxylase and -24-hydroxylase have been measured extensively in fowl, no methods for assay of these enzymes have been validated for the mammal. Inhibitory activity present in all mammalian tissues is a hindrance to accurate measurement The mechanism by which protein components from rat tissues reduce chick 25OHDS-1-hydroxylase activity were studied by a...
متن کاملLocalization of 25-hydroxyvitamin D3 1 alpha-hydroxylase and 24-hydroxylase along the rat nephron.
Defined nephron segments were microdissected from the kidney of vitamin D-deficient rats, normal rats, and normal rats treated with 1 alpha, 25-dihydroxyvitamin D3 [1 alpha, 25-(OH)2D3]. Tubule segments were incubated with 3H]labeled 25-hydroxyvitamin D3 and the rates of production of 3H]labeled 1 alpha, 25-(OH)2D3 and 24,25-dihydroxyvitamin D3 [24,25-(OH)2D3] were determined. Nephron segments ...
متن کاملCloning of human 25-hydroxyvitamin D-1 alpha-hydroxylase and mutations causing vitamin D-dependent rickets type 1.
The secosteroid hormone, 1,25-dihydroxyvitamin D [1,25(OH)2D], plays a crucial role in normal bone growth, calcium metabolism, and tissue differentiation. The key step in the biosynthesis of 1,25(OH)2D is its 1 alpha-hydroxylation from 25-hydroxyvitamin D (25-OHD) in the kidney. Because its expression in the kidney is very low, we cloned and sequenced cDNA for 25-OHD-1 alpha-hydroxylase (P450c1...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1992
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)50758-x