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Enzyme
Compound
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Query: EC:3.1.3.1 (
alkaline phosphatase
)
47,916
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The alpha 2-HS-glycoprotein is a plasma protein synthesized in liver and enriched in bone. The concentration of alpha 2-HS-glycoprotein dynamically changes in various physiological conditions and is highest in bone during growth, suggesting that it is involved in regulation of endochondral ossification. Northern blot analysis demonstrated that mRNA transcripts from growth zone and resting zone costochondral chondrocyte cultures hybridized with alpha 2-HS-glycoprotein cDNA. However, a difference of mRNA transcript size was observed, with chondrocyte mRNA transcripts being 2.2 kb, while mRNA isolated from liver was 1.6 kb. Presence of alpha 2-HS-glycoprotein in cartilage cells was found by immunohistochemical staining of human fetal epiphyses using anti-human alpha 2-HS-glycoprotein antibody. To understand the role of alpha 2-HS-glycoprotein in cartilage growth, the effects of exogenous alpha 2-HS-glycoprotein were correlated with
alkaline phosphatase
(ALPase) and
phospholipase A2
(PA2) activity in the chondrocyte cultures. Alkaline phosphatase specific activity was stimulated by alpha 2-HS-glycoprotein at concentrations between 0.25 and 1.25 micrograms/mL in the growth zone and resting zone cultures 2.7 and 2.0-fold, respectively. Matrix vesicle PA2 activity was increased only in the growth zone chondrocyte cultures. These results suggested that alpha 2-HS-glycoprotein may contribute to the regulation of the expression of the chondrocyte phenotype. Steady state mRNA levels of ALPase were analyzed in chondrocytes after additions of alpha 2-HS-glycoprotein. The ALPase mRNA levels remained stationary during the stimulation of enzymatic activity, indicating that the effect of alpha 2-HS-glycoprotein upon
alkaline phosphatase
activity is not at the transcriptional level.
...
PMID:Alpha 2-HS-glycoprotein: expression in chondrocytes and augmentation of alkaline phosphatase and phospholipase A2 activity. 205 37
1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase,
alkaline phosphomonoesterase
, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase,
phospholipase A
, L-amino acid oxidase and protease activities of 31 samples of venom from three species of Agkistrodon (A. bilineatus, A. contortrix and A. piscivorus) and 10 venom samples from five other related species belonging to the same tribe of Agkistrodontini were examined. 2. The results indicate that interspecific differences in certain biological activities of the Agkistrodon venoms are more marked than individual variations of the activities, and that these differences can be used for differentiation of the species. Particularly useful for this purpose are the phosphodiesterase, arginine ester hydrolase and anticoagulant activities of the venoms. 3. Venoms of the subspecies of A. contortrix and A. piscivorus do not differ significantly in their biological activities.
...
PMID:A comparative study of the biological activities of venoms from snakes of the genus Agkistrodon (moccasins and copperheads). 215 74
1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase,
alkaline phosphomonoesterase
, 5'-nucleotidase, arginine ester hydrolase,
phospholipase A
, L-amino acid oxidase and protease activities of 26 samples of venoms of 13 taxa of Vipera were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. The results indicate the presence of certain common characteristics among the venoms, particularly if V. russelli is excluded from the comparison. The results also support the recently proposed reassignment of V. russelli to a separate genus. 3. The data show that information on venom biological properties can be used for differentiation of venoms of many species of Vipera. Particularly useful for this purpose are the protease, phosphodiesterase,
phospholipase A
and the procoagulant activities and the Sephadex G-75 gel filtration patterns of the venoms.
...
PMID:A comparative study of the biological properties of venoms from snakes of the genus Vipera (true adders) 217 67
Transforming growth factor-beta (TGF beta) serves an important role in extracellular matrix formation by stimulating the production of numerous extracellular matrix proteins by connective tissue cells and by osteoblasts or bone-forming cells. TGF beta has been shown to stimulate
alkaline phosphatase
(ALPase) activity in the rat osteoblast-like osteosarcoma cell line ROS 17/2.8. Previous studies have shown that this enzyme is elevated during calcification of bone and that it is enriched in matrix vesicles, an extracellular organelle associated with initial hydroxyapatite formation. To test the hypothesis that TGF beta plays a role in regulating mineral deposition in the matrix, the effects of TGF beta on ALPase and
phospholipase A2
, two enzymes associated with mineralization, were examined. ROS 17/2.8 cells were cultured at high and low density with recombinant human TGF beta (0.1-10 ng/ml) to examine the influence of cell maturation on response to TGF beta. Maximal stimulation of ALPase activity in the low density cultures was seen at 5 ng/ml; in high-density cultures, there was further stimulation at 10 ng/ml. There was a dose-dependent increase in ALPase activity seen in the matrix vesicles and plasma membranes in both types of cultures. Matrix vesicle ALPase exhibited a greater response to factor than did the plasma membrane enzyme. However, in low-density cultures, the two membrane fractions exhibited a parallel response with greatest activity consistently in the matrix vesicles. There was a dose-dependent increase in
phospholipase A2
-specific activity in the plasma membranes and matrix vesicles of both high- and low-density cultures. In agreement with previous studies, TGF beta inhibited cellular proliferation 50%. The results show that addition of TGF beta stimulates the activity of enzymes associated with calcification. The effect of TGF beta is dependent on the stage of maturation of the cell. This study indicates that TGF beta may play an important role in induced bone formation, calcification, and fracture repair in addition to its role in promoting chondrogenesis.
...
PMID:Stimulation of plasma membrane and matrix vesicle enzyme activity by transforming growth factor-beta in osteosarcoma cell cultures. 224 23
Endochondral ossification in bone development and repair, and in induced bone formation in mesenchymal tissues, involves recruitment of mesenchymal cells, their differentiation into chondrocytes, and calcification of the cartilagenous matrix. Stimulation of proteoglycan synthesis is used as a biochemical marker of chondrogenesis, however it does not distinguish among chondrogenic phenotypes. Chondrocytes derived from the resting zone and adjacent growth zone cartilage of the costochondral junction of young rats, produce matrix vesicles in culture which are enriched in
alkaline phosphatase
specific activity with respect to the plasma membrane. Matrix vesicles isolated from cultures of neonatal rat muscle mesenchymal cells are not enriched in this enzyme activity. Alkaline phosphatase in matrix vesicles produced by growth zone chondrocytes is stimulated by 1,25(OH)2D3; enzyme in matrix vesicles produced by resting zone chondrocytes is stimulated by 24,25(OH)2D3; enzyme in matrix vesicles isolated from mesenchymal cell cultures is responsive to neither metabolite. Matrix vesicle
phospholipase A2
is stimulated by 1,25(OH)2D3 in growth zone chondrocytes cultures; inhibited by 24,25(OH)2D3 in resting zone chondrocyte cultures; and is unaffected by either metabolite in mesenchymal cell cultures. These observations suggest that matrix vesicle production, as defined by
alkaline phosphatase
enrichment, and responsiveness of matrix vesicle enzymes to vitamin D metabolites, can be used as markers of phenotypic maturation during chondrogenesis in vivo and in vitro.
...
PMID:Matrix vesicles as a marker of endochondral ossification. 233 26
It is now well established that epidermis, like many other tissues, contains a
phospholipase A2
that is responsible for the initiation of the arachidonic acid cascade. Here we report that human epidermis also contains a second, quite distinct enzyme of the
phospholipase A2
group, which is unique in its extreme activity against phospholipids in true solution. It also differs from the classic cutaneous enzyme in that (a) its activity is not reduced by pretreatment of the skin with corticosteroids in vivo nor by treatment of the epidermal homogenate with
alkaline phosphatase
in vitro, and (b) its activity is reduced, rather than increased, in the lesions of inflammatory diseases such as psoriasis. The enzyme seems to occur mainly in fully differentiated keratinocytes, its level being low in the basal cell layer of epidermis and in keratinocytes cultured in vitro. On the basis of these observations, we suggest that this new
phospholipase A2
is responsible for the degradation of phospholipids that accompanies the terminal keratinization process.
...
PMID:A unique phospholipase A2 in human epidermis: its physiologic function and its level in certain dermatoses. 244 92
Since our previous experiments suggested that glycosylation-inhibiting factor (GIF) is a phosphorylated derivative of a phospholipase inhibitory protein, we determined whether other well-known phospholipase inhibitors may have similar biological activities. The results showed that
phospholipase A2
(
PLA2
) inhibitors, such as recombinant human lipocortin I and ONO-RS-082, could switch T cell hybridoma 12H5 cells from the formation of glycosylated IgE-binding factors (IgE-BF) to the formation of unglycosylated IgE-BF, whereas neomycin, a phospholipase C inhibitor, failed to affect the nature of IgE-BF formed by the cells. The minimum concentrations of lipocortin I and ONO-RS-082 required for switching the 12H5 cells to the formation of unglycosylated IgE-BF were comparable to or less than IC50 of the inhibitors for
PLA2
. The ability of partially purified GIF to switch the 12H5 cells to the formation of unglycosylated IgE-BF was markedly enhanced by treatment of the preparation with
alkaline phosphatase
. It was also found that lipocortin I and ONO-RS-082, but not neomycin, facilitated the generation of GIF-producing T cells. When spleen cells of ovalbumin (OVA)-primed BDF1 mice were stimulated with homologous antigen and the activated T cells were propagated by recombinant IL-2 in the presence of GIF, lipocortin I, or ONO-RS-082, T cells obtained in the cultures constitutively produced their own GIF. Antigenic stimulation of the T cells induced the formation of unglycosylated IgE-BF and GIF with an affinity for OVA.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effect of phospholipase A2 inhibitors on mouse T lymphocytes. I. Phospholipase A2 inhibitors exert similar immunological activities as glycosylation inhibiting factor. 253 36
Trimeresurus wagleri (speckled pit viper) venom exhibited the usual set of enzyme activities occurring in pit viper venoms but the content of
alkaline phosphomonoesterase
was unusually high, whereas the proportions of protease and arginine ester hydrolase were very low. The venom also exhibited weak thrombin-like activity but did not exhibit hemorrhagic or anticoagulant activity. Analysis of the Sephadex G-200 gel filtration fractions of the venom indicated that the lethal fraction was a low mol.wt protein, and that fractions exhibiting phosphodiesterase,
phosphomonoesterase
, arginine ester hydrolase, thrombin-like enzyme, L-amino acid oxidase and
phospholipase A
activities were not lethal. Two lethal toxins, designated as wagleri toxins 1 and 2, were isolated from the venom using Sephadex G-50 gel filtration chromatography followed by SP-Sephadex C-25 ion exchange chromatography. The mol.wts of the two toxins were 8900 by gel filtration. The LD50 (i.v.) values in mice for wagleri toxins 1 and 2 are 0.17 microgram/g and 0.19 microgram/g, respectively.
...
PMID:The enzymatic activities and lethal toxins of Trimeresurus wagleri (speckled pit viper) venom. 254 3
1. The lethalities, anticoagulant effects, hermorrhagic, thrombin-like enzyme, hyaluronidase, protease, arginine ester hydrolase, 5'-nucleotidase, L-amino acid oxidase,
alkaline phosphomonoesterase
, phosphodiesterase and
phospholipase A
activities of twenty-three samples of venoms from twelve species of Asian lance-headed pit vipers (genus Trimeresurus) were examined. 2. The results indicate that notwithstanding individual variations in venom properties, the differences in biological properties of the Trimeresurus venoms can be used for the differentiation of venoms from different species of Trimeresurus. 3. The results also suggest that differences in the biological properties of snake venoms are useful parameters in the classification of snake species. 4. Our results indicate that venoms from the species T. okinavensis exhibited biological properties markedly different from other Trimeresurus venoms examined. This observation supports the recently proposed reclassification of T. okinavensis as a member of the genus Ovophis, rather than the genus Trimeresurus.
...
PMID:A comparative study of the enzymatic and toxic properties of venoms of the Asian lance-headed pit viper (Genus Trimeresurus). 255 29
There have been many reports recognizing vascular changes on pressure side of periodontal tissues during orthodontic tooth movement. The vascular changes cause local hypoxia which seems to affect the phenotypes of periodontal tissue cells. In order to clarify the effect of hypoxia on proliferation and function of periodontal tissue cells, DNA content,
alkaline phosphatase
(
ALP
) activity and prostaglandin E2 (PGE2) production under a hypoxic condition in both periodontal ligament fibroblasts (PLF) and osteoblastic cells (MC3T3-E1 cells) were examined in vitro. PLF were cultured from human periodontium and identified by both morphologic characterization and presence of
ALP
. The results obtained were as follows: 1. Under 10% O2 condition, the activity of proliferation in PLF did not change but that of osteoblasts was inhibited. 2.
ALP
activity in PLF was stimulated but that of osteoblasts was inhibited under the hypoxic condition. 3. Production of PGE2 in osteoblasts increased after 7 days of hypoxia though that in PLF decreased. In addition, the enhancement of PGE2 production in osteoblasts was due to activation of both
phospholipase A2
and PGE2-synthesizing enzymes. 4. From the orthodontic point of view, hypoxia on the pressure side may induce bone resorption by inhibiting mineralization activity of osteoblasts and enhancing production of PGE2 in osteoblasts.
...
PMID:[Study on proliferation and function of periodontal ligament fibroblasts and osteoblastic cells under hypoxia]. 262 92
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