Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug 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)

To investigate the hepatic abnormalities accompanying experimental protoporphyria due to griseofulvin (GF), liver function test values and porphyrin levels in mice were assayed at days 2, 4, 8, and 16 after starting the administration of 0.5% GF feed. Furthermore, in an attempt to elucidate the harmful effects of GF on liver functions, the above mentioned assay was also performed after the feed was discontinued in mice given 0.5% GF feed for 16 days. The hepatic protoporphyrin (PP) level had already risen by day 2, but the erythrocytic PP level was within normal limits at that time. Hepatic PP levels increased gradually, followed by an increase in erythrocytic PP levels. The variation in liver function test values roughly paralleled the porphyrin levels. Over the time span of the response to GF, the variations in the serum glutamate oxaloacetate transaminase (S-GOT) levels, serum glutamate pyruvate transaminase (S-GPT) levels, and leucine amino peptidase (LAP) levels resembled those in hepatic PP. On the other hand, the changes in alkaline phosphatase (ALP) levels paralleled those of the erythrocytic PP levels. Erythrocytic and fecal protoporphyrin levels decreased to the normal level one month after the discontinuation of GF administration, but the hepatic protoporphyrin level still was 53.6 times higher than the normal level two months after switching to normal feed. The values of liver function tests had returned to within the normal range after one month. By the fourth day after the administration of GF, a brown pigmented material could be observed around the hepatocytes and the Glisson sheath; the amount of this material increased day by day.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Experimental murine protoporphyria induced by griseofulvin (GF): the relationship between hepatic porphyrin levels and liver function test values in mice treated with GF. 822 9

A chimeric precursor interlinked by an arginine residue between the full-length signal sequence of alkaline phosphatase and the eukaryotic cytoplasmic cytochrome b5 was constructed. Expression of the chimeric precursor protein in Escherichia coli resulted in efficient export of spectrally authentic cytochrome b5 into the periplasm [Karim, Harding, Evans, Kaderbhai and Kaderbhai (1993) Bio/Technology 11, 612-618]. On sequencing, the apparent absence of arginine at the N-terminus of the secreted cytochrome b5 implied that the chimera was either miscleaved by signal peptidase or further processed following signal excision by an uncharacterized peptidase. The influence of the N-terminal region of cytochrome b5 on the unusual processing of the chimeric precursor was investigated by engineering a number of variant forms in which the region between Arg+1 and the mature portion of cytochrome b5 was extended and varied. Observations of the in vivo processed patterns of these variant cytochrome b5 forms exported into the periplasm revealed that the absence of arginine was due to neither miscleavage of the translocated precursor by the signal peptidase nor the nature of the early region of cytochrome b5. In fact, the selective excision of the arginine residue occurred subsequent to signal sequence deletion by an aminopeptidase which was sensitive to the metal chelator o-phenanthroline. We show that this aminopeptidase also participates in the trimming of the N-terminal arginine residue of the bacterial alkaline phosphatase to generate the three isoenzymes in the periplasm.
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PMID:Processing of chimeric mammalian cytochrome b5 precursors in Escherichia coli: reaction specificity of signal peptidase and identification of an aminopeptidase in post-translocational processing. 835 42

Extracellular matrix regulation of intestinal epithelial differentiation may affect development, differentiation during migration to villus tips, healing, inflammatory bowel disease, and malignant transformation. Cell culture studies of intestinal epithelial biology may also depend on the matrix substrate used. We evaluated matrix effects on differentiation and proliferation in human intestinal Caco-2 epithelial cells, a model for intestinal epithelial differentiation. Proliferation, brush border enzyme specific activity, and spreading were compared in cells cultured on tissue culture plastic with interstitial collagen I and the basement membrane constituents collagen IV and laminin. Each matrix significantly increased alkaline phosphatase, dipeptidyl peptidase, lactase, sucrase-isomaltase, and cell spreading in comparison to plastic. However, the basement membrane proteins collagen IV and laminin further promoted all four brush border enzymes but inhibited spreading compared to collagen I. Proliferation was most rapid on type I collagen and slowest on laminin and tissue culture plastic. Basement membrane matrix proteins may promote intestinal epithelial differentiation and inhibit proliferation compared with interstitial collagen I.
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PMID:Regulation of human (Caco-2) intestinal epithelial cell differentiation by extracellular matrix proteins. 866 Sep 18

PA28, also referred to as 11S regulator, is a potent activator of the peptidase activities of the proteasome (multicatalytic proteinase complex). Although the role(s) of PA28-20S proteasome complexes in cellular proteolytic processes remain to be defined, these particles have been implicated in antigen processing of major histocompatibility complex (MHC) class I molecules. Our results demonstrate that PA28 is phosphorylated as evidenced by 32P incorporation into a single PA28 species in rabbit reticulocytes. In reticulocytes as well as human erythrocytes, PA28 is normally found in a phosphorylated state as detected by phosphoserine antibody. In human erythrocytes, this antibody recognizes three polypeptides which are also detected by antibody to PA28 on Western blot analysis. Dephosphorylation with alkaline phosphatase treatment completely abolishes the ability of PA28 to activate hydrolysis of Suc-Leu-Leu-Val-Tyr by proteasomes. After exposure to phosphatase, the three polypeptides are no longer recognized by phosphoserine antibody, although binding to PA28 antibody is unaffected. These results suggest that phosphorylation may function in transduction of cytokine and growth factor signals that, in turn, modulate antigen presentation and other processes which involve PA28-20S proteasome complexes.
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PMID:Phosphorylation of the proteasome activator PA28 is required for proteasome activation. 878 Jul 2

Although a substantial coronary angiogenesis occurs after thyroid hormone treatment, its regulation and relationship to cardiac hypertrophy are not understood. This study was designed to determine (1) the onset of capillary proliferation, (2) the sites of capillary proliferation, and (3) whether basic fibroblast growth factor (bFGF) upregulation occurs in response to thyroxine administration. Male Sprague-Dawley rats were injected daily with L-thyroxine (T4, 0.2 mg/kg s.c.). Bromodeoxyuridine labeling of capillary endothelial cells increased during the first 24 hours of treatment and peaked after 2 days of treatment. Northern blot analysis revealed a slight increase in bFGF mRNA during this period, followed by a doubling of expression by 48 hours, at which time bFGF protein was also increased. In situ hybridization, used to localize bFGF mRNA, showed an increase in transcripts within 24 hours after T4. This enhancement was uniform in the epimyocardium and endomyocardium. Histochemical analysis (double staining for alkaline phosphatase and dipeptidyl peptidase) of frozen sections, used to discriminate capillary profiles as arteriolar and venular, respectively, showed that growth occurred in the latter, since the percentage of capillary profiles positive for dipeptidyl peptidase was higher than the control value after 4 days of T4 administration. These data indicate that in the thyroxine model of cardiac hypertrophy (1) capillary DNA synthesis occurs after a single injection of thyroxine, (2) capillary growth coincides with an upregulation in bFGF mRNA and increase in bFGF protein, and (3) proliferation occurs in the venular capillaries.
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PMID:Early coronary angiogenesis in response to thyroxine: growth characteristics and upregulation of basic fibroblast growth factor. 952 63

Acute hypertension provokes a rapid decrease in proximal tubule sodium reabsorption with a decrease in basolateral membrane sodium-potassium-ATPase activity and an increase in the density of membranes containing apical membrane sodium/hydrogen exchangers (NHE3) [Y. Zhang, A. K. Mircheff, C. B. Hensley, C. E. Magyar, D. G. Warnock, R. Chambrey, K.-P. Yip, D. J. Marsh, N.-H. Holstein-Rathlou, and A. A. McDonough. Am. J. Physiol. 270 (Renal Fluid Electrolyte Physiol. 39): F1004-F1014, 1996]. To determine the reversibility and specificity of these responses, rats were subjected to 1) elevation of blood pressure (BP) of 50 mmHg for 5 min, 2) restoration of normotension after the first protocol, or 3) sham operation. Systolic hypertension increased urine output and endogenous lithium clearance three- to fivefold within 5 min, but these returned to basal levels only 15 min after BP was restored. Renal cortex lysate was fractionated on sorbitol gradients. Basolateral membrane sodium-potassium-ATPase activity (but not subunit immunoreactivity) decreased one-third to one-half after BP was elevated and recovered after BP was normalized. After BP was elevated, 55% of the apical NHE3 immunoreactivity, smaller fractions of sodium-phosphate cotransporter immunoreactivity, and apical alkaline phosphatase and dipeptidyl-peptidase redistributed to membranes of higher density enriched in markers of the intermicrovillar cleft (megalin) and endosomes (Rab 4 and Rab 5), whereas density distributions of the apical cytoskeleton protein villin were unaltered. After 20 min of normalized BP, all the NHE3 and smaller fractions of the other apical membrane proteins returned to their original distributions. These findings suggest that the dynamic regulation of proximal tubule sodium transport by acute changes in BP may be mediated by rapid reversible regulation of sodium pump activity and relocation of apical sodium transporters.
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PMID:Reversible effects of acute hypertension on proximal tubule sodium transporters. 957 7

Intestinal epithelial cell differentiation is closely regulated during normal cell renewal, maturation, and malignant transformation. Since tyrosine phosphorylation influences differentiation in other cell types and has been reported to vary between crypt cells to differentiated villus tip cells, we investigated the influence of tyrosine phosphorylation in colonocyte differentiation, by using human colonic Caco-2 cells as a model and expression of the brush border enzymes alkaline phosphatase (AKP) and dipeptidyl peptidase (DPDD) as differentiation markers. We studied three tyrosine kinase inhibitors with different modes of action and specificities, viz., genistein, erbstatin analog (EA), and tyrphostin, and the tyrosine phosphatase inhibitor sodium orthovanadate. AKP- and DPDD-specific activities were assayed in protein-matched cell lysates by synthetic substrate digestion. We also correlated the effects of these agents on brush border enzyme activity with tyrosine phosphorylation of phosphoproteins by Western blotting. Genistein (5-75 mg/ml) dose-dependently stimulated AKP and DPDD with a maximal stimulation at 75 mg/ml by 158.6+/- 17.5% and 228.6+/-37.1% of control values, respectively (n=12, P<0.001). The inactive analog genistin had no effect. Tyrphostin (25 mM) similarly stimulated AKP and DPDD by 138. 6+/-6.6% and 131.8+/-1.5% of control values (n=12, P<0.001). Unexpectedly, EA (0.1-10 mM) had the opposite effect, inhibiting AKP- and DPDD-specific activity significantly at 10 mM with a maximal 14.8+/-6.4% and 26.5+/-2.5% of control values (n=12, each P<0.001). Sodium orthovanadate had a discordant effect on these two differentiation markers. Orthovanadate dose-dependently increased AKP to a maximal 188.5+/-16.1% of basal activity at 1.5 mM but decreased DPDD activity at 1.5 mM to 47.2+/-3.8% (n=9, P<0.001 each). The effects of each agent were preserved when proliferation was blocked with mitomycin C, suggesting that the modulation of phenotype by these agents was independent of any effects of proliferation. The tyrosine phosphorylation of several phosphoprotein bands was affected differently by these agents. In particular, the tyrosine phosphorylation of one 70-kDa to 71-kDa band was increased by genistein and tyrophostin but deceased by EA. The different effects of these modulators of tyrosine kinase activity raise the possibility that at least two independent enzymes or pathways regulating tyrosine phosphorylation modulate intestinal epithelial differentiation. Furthermore, tyrosine phosphorylation of the 70-kDa to 71-kDa phosphoprotein may be important in the intracellular signaling by which intestinal epithelial cell differentiation is controlled.
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PMID:Effects of modulation of tyrosine phosphorylation on brush border enzyme activity in human Caco-2 intestinal epithelial cells. 958 12

Blood activities of hepatocellular enzymes such as lactate dehydrogenase (LDH), glutamic pyruvic transaminase (GPT) and glutamic oxalacetic transaminase (GOT) peaked at 12 hours after a single intraabdominal injection of ferric nitrilotriacetate (Fe(3+)-NTA) in rats. Enzymes such as alkaline phosphatase (ALP) and leucin amino peptidase (LAP) originating in the capillary bile ducts or bile secretory liver cells were also released into the blood between 6-24 hours after intraabdominal injection of Fe(3+)-NTA in rats. Furthermore, hyperoxidation of lipids occurred in rat hepatic cell membranes, reaching a peak 6 hours after intraabdominal injection of Fe(3+)-NTA. It was found that a single prior 0.5 Gy whole body X-ray irradiation significantly increased superoxide dismutase (SOD) activities and suppressed above-mentioned symptoms of transient hepatopathy in rats.
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PMID:Inhibitory effects of prior low dose X-ray irradiation on Fe(3+)-NTA-induced hepatopathy in rats. 980 33

Abstract The Pomeranian Bight in the southern Baltic Sea is characterized by a huge input of nutrients from the Oder river. This input shows seasonal variation. In winter, the nutrients are introduced in inorganic form. Particulate organic material is dominant in the growth season (summer/autumn). From 1993 to 1996, extracellular enzyme activities (alkaline phosphatase, peptidase, alpha-, beta-glucosidase, and chitinase) were investigated to describe microbial reaction to the input of organic material and the modification of introduced material. The distribution patterns of extracellular enzyme activities in salinity gradients were studied, in response to the nutrient load. These activities were distinctly lower in winter than in summer and autumn. A close relationship to other biological parameters (Chl a, POC, PON) was observed during the growth season, but not in winter. Changes in peptidase and phosphatase activities between summer and autumn were also observed. The peptidase activity was 9 to 72 times higher in autumn than in summer. In contrast, the alkaline phosphatase activity was 5 to 30 times higher in summer than in autumn. The organic compound turnover rate/hydrolysis rate (To/Hr) ratio is a relative index which describes the coupling of enzymatic hydrolysis and utilization of monomers from investigated substrates (carbohydrates and proteins). In summer, after dilution, the raised To/Hr quotients of glucose indicated limited importance for hydrolysis products in bacterial turnover. The increased demand for glucose resulted in a parallel decrease in monosaccharides. In autumn, the relationship between the turnover of glucose and amino acids and the supply of these substances by enzymatic degradation remained at the same level.
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PMID:Extracellular Enzyme Activities in Relation to Hydrodynamics in the Pomeranian Bight (Southern Baltic Sea). 985 5

Histochemical studies of enzyme activities and structural elements in Gyrodactylus derjavini Mikailov, 1975 parasitizing fins of Oncorhynchus mykiss Walbaum were conducted. Marked activities of non-specific esterase, acid phosphatase, alkaline phosphatase and amino-peptidase were found in the intestinal caeca of the parasite. A strong activity of acetylcholinesterase was seen in the nervous system. Extraintestinal non-specific and eserine-sulphate resistant esterase was localized in the distal part of the hamulus sheath. Activities of peroxidase and glucuronidase were not detected. In the embryo, developing hamuli were enclosed in a sheath rich in phospholipids. Deposits of neutral lipids were sparse. The fully developed ventral and dorsal hamulus bars stained strongly for calcium. Lectin binding assays showed a mannose rich region in the cephalic duct openings, strong reactions for galactose in the glycocalyx whereas reactions for lactose were weak. These findings are discussed with respect to the parasite-host relationship.
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PMID:Histochemical characteristics of Gyrodactylus derjavini parasitizing the fins of rainbow trout (Oncorhynchus mykiss). 986 92


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