Topic
Alkaline phosphatase
About: Alkaline phosphatase is a research topic. Over the lifetime, 20218 publications have been published within this topic receiving 540547 citations. The topic is also known as: Alkaline_phosphatase & IPR001952.
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TL;DR: It is shown that the partially dephosphorylated proteins no longer support osteoclast binding, indicating that the secretion of TRAP from osteoclasts into the resorption area could exert a regulatory influence on the attachment of the cells to the bone surface.
313 citations
TL;DR: Induction of increased activities of lysozyme and complement may, at least in part, explain the mechanisms by which glucan induces protection against bacterial pathogens in salmon.
313 citations
TL;DR: It is found that human myeloma cells suppress the formation of human osteoblast progenitors in bone marrow (BM) cultures and the potential contribution of interleukin-7 (IL-7) in the inhibitory effect on osteooblast formation and RUNX2/CBFA1 activity by human myELoma cells in coculture is shown.
312 citations
TL;DR: Elevated concentrations of Ca(2+) and PO(4)(3-) are not sufficient for medial vascular calcification because of inhibition by pyrophosphate, and OPN is not an endogenous inhibitor of calcification in rat aorta.
Abstract: Hyperphosphatemia is thought to underlie medial vascular calcification in advanced renal failure, but calcification can occur in other conditions in the absence of hyperphosphatemia, indicating that additional factors are important. To identify these factors, a model of medial calcification in rat aorta in vitro was developed. Aortic rings from rats were incubated in serum-free medium for 9 d, and calcification was measured as incorporation of (45)Ca and confirmed by histology and x-ray diffraction. No calcification occurred in normal vessels despite elevated free Ca(2+) and PO(4)(3-) concentrations of 1.8 mM and 3.8 mM, respectively, but mechanical injury resulted in extensive calcification in the media. Co-incubation studies revealed that normal aortas produced a soluble inhibitor of calcification in injured vessels that was destroyed by alkaline phosphatase. Culture of normal aortas with alkaline phosphatase resulted in calcification of the elastic lamina identified as hydroxyapatite by x-ray diffraction. This effect of alkaline phosphatase was not due to dephosphorylation of osteopontin (OPN), and calcification was not increased in aortas from OPN-deficient mice. The inhibitor was identified as pyrophosphate on the basis of the calcification induced in aortas cultured with inorganic pyrophosphatase, the inhibition of calcification in injured aortas by pyrophosphate, and the production of inhibitory levels of pyrophosphate by normal aortas. No calcification occurred under any conditions at a normal PO(4)(3-) concentration. It is concluded that elevated concentrations of Ca(2+) and PO(4)(3-) are not sufficient for medial vascular calcification because of inhibition by pyrophosphate. Alkaline phosphatase can promote calcification by hydrolyzing pyrophosphate, but OPN is not an endogenous inhibitor of calcification in rat aorta.
310 citations
TL;DR: Liver homogenates have been submitted to quantitative fractionation by differential centrifugation and a final supernate (S) have been obtained, and the biochemical composition of the microsomal fraction has been established from the assay and distribution pattern of 25 enzymatic and chemical constituents.
Abstract: Liver homogenates have been submitted to quantitative fractionation by differential centrifugation. Three particulate fractions: N (nuclear), ML (large granules), and P (microsomes), and a final supernate (S) have been obtained. The biochemical composition of the microsomal fraction has been established from the assay and distribution pattern of 25 enzymatic and chemical constituents. These included marker enzymes for mitochondria (cytochrome oxidase), lysosomes (acid phosphatase and N-acetyl-beta-glucosaminidase), and peroxisomes (catalase). The microsomal preparations were characterized by a moderate contamination with large cytoplasmic granules (only 6.2% of microsomal protein) and by a high yield in microsomal components. Enzymes such as glucose 6-phosphatase, nucleoside diphosphatase, esterase, glucuronyltransferase, NADPH cytochrome c reductase, aminopyrine demethylase, and galactosyltransferase were recovered in the microsomes to the extent of 70% or more. Another typical behavior was shown by 5'-nucleotidase, alkaline phosphatase, alkaline phosphodiesterase I, and cholesterol, which exhibited a "nucleomicrosomal" distribution. Other complex distributions were obtained for several constituents recovered in significant amount in the microsomes and in the ML or in the S fraction.
309 citations