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

---

Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 17 year old man with longstanding hypocalcemia and hyperphosphatemia presented with incapacitating bone pain and progressive weakness nad bowing of the legs. The serum abnormalities were due to idiopathic hypoparathyroidism as evidenced by a decreased serum concentration of parathyroid hormone and an appropriate rise in urinary cyclic AMP and phosphate excretion, and serum calcium concentration, in response to exogenously administered parathyroid extract. The serum concentration of 1,25-dihydroxycholecalciferol was appropriately decreased. The bone findings were due to osteomalacia as documented by physical findings, bone roentgenograms, and bone biopsy. Normal renal tubular function, blood pH, and serum concentration of 25-hydroxycholecalciferol and elevated serum alkaline phosphatase excluded the common causes of osteomalacia. The data are consistent with the hypothsis that lack of parathyroid hormone causes both hypocalcemia and a decreased serum concentration of 1,25-dihydroxycholecalciferol which, in turn, limit the availability of calcium and cause defective synthesis of bone matrix resulting in abnormal mineralization.
...
PMID:Hypoparathyroidism: a possible cause of osteomalacia . 87 58

Rat small bowel was perfused in vivo and ex vivo in the absence of biliary and pancreatic secretion. Intraluminal release of sucrase, alkaline phosphatase, aminopeptidase and enterokinase was significantly increased after administration of PG E1 and E2 1 and 5 microgram/kg. This suggests a direct stimulation of the intestinal mucosa, which might be mediated through cyclic AMP; dibutyryl cAMP significantly stimulates intraluminal release of proteins, sucrase and enterokinase.
...
PMID:Prostaglandins E1 and E2 stimulate release of intestinal brush border enzymes. 90 72

The 5'-phosphomonoesterase activity of 5'-nucleotidase (EC 3.1.3.5) and alkaline phosphatase (EC 3.1.3.5) participates in the catabolism of purine ribonucleotides to uric acid in humans. Initial velocity studies of 5'-nucleotidase suggest a sequential mechanism of interaction between AMP nad MgCl2, with a Km of 14 and 3 muM, respectively. With product inhibition studies the apparent Ki's for adenosine, inosine, cytidine, and inorganic phosphate were 0.4, 3.0, 5.0, and 42 mM, respectively. A large number of nucleoside mono-, di-, and tri-phosphate compounds were inhibitors of the enzyme. Allopurinol ribonucleotide, ADP, or ATP were competitive inhititors when AMP was the substrate, with a Ki slope of 120 muM. The phosphomonoesterase activity of human placental microsomal alkaline phosphatase had a pH optimum of 10.0 and had only 18% of maximum activity at pH 7.4. Substrates and inhibitors included almost any phosphorylated compound. The Km for AMP was 0.4 mM and the apparent Ki for Pi was 0.6 mM. Activity was increased only 19% by 5 mM MgCl2. These observations suggest that 5'-nucleotidase and alkaline phosphatase may be inhibited by ATP and Pi, respectively, under normal intracellular conditions, and that AMP may be preferentially hydrolyzed by 5'-nucleotidase.
...
PMID:Purine catabolism in man: inhibition of 5'-phosphomonesterase activities from placental microsomes. 101 16

There are several reports on the weak contractile activity of uterus in the prolonged pregnancy. Some investigations showed that the weak contractile activity is associated with the low contents of RNA, proteins and glycogen in the myometrial cell. The material was obtained from caesarean sections in 27 patients with prolonged pregnancy and 30 patients with normal pregnancy. It was found a diminished contents of glycogen and lipids in the myometrial cell, and a decreased activity of phosphorylase and alkaline phosphatase but an increased activity of acid phosphatase. The lower content of energetic material and changes in the activity of the enzymes shows that the metabolism of the myometrial cell is impaired in prolonged pregnancy. One can suppose that the lowered level of estrogens is responsible for the described changes. The lower level of estrogens probably causes the decrease of 3'5' AMP in the myometrial cell with the impaired cell metabolism as a consequence. This may be one of the causes of a weak uterine contractile activity in the prolonged pregnancy.
...
PMID:[Histochemical studies of the myometrium in the prolonged pregnancy]. 121 Aug 81

The speB gene of Escherichia coli encodes agmatine ureohydrolase (AUH), a putrescine biosynthetic enzyme. The speB gene is transcribed either from its own promoter or as a polycistronic message from the promoter of the speA gene encoding arginine decarboxylase. Two open reading frames (ORF1 and ORF2) are present on the strand complementary to speB; approximately 90% of ORF2 overlaps the speB coding region. Analysis of transcriptional and translational fusions of ORF1 or ORF2 to lacZ revealed that ORF1 encoded a novel protein while ORF2 was not transcribed. Deletion of ORF1 from a plasmid containing ORF1, ORF2, and speB reduced the activity of AUH by 83%. In contrast, the presence of plasmid-encoded ORF1 caused an 86% increase in chromosomally encoded AUH activity. ORF1 did not stimulate alkaline phosphatase expressed from a phi(speB-phoA) transcriptional fusion encoded on the same plasmid. Western analysis (immunoblot) of a phi(ORF1-lacZ) translational fusion revealed that ORF1 encodes a 25.3-kDa protein. Agmatine induced transcription of phi(speB-phoA) but not phi(speA-phoA) fusions. Consequently, agmatine affects selection between the monocistronic and the polycistronic modes of speB transcription. In contrast, cyclic AMP (cAMP) repressed AUH activity of chromosomally encoded AUH but had no effect on plasmid-borne speB nor phi(speB-phoA). It is concluded that ORF1 encodes a protein which is a posttranscriptional regulator of speB, agmatine induces speB independent of speA, and cAMP regulates speB indirectly.
...
PMID:Influence of cyclic AMP, agmatine, and a novel protein encoded by a flanking gene on speB (agmatine ureohydrolase) in Escherichia coli. 131 91

1. Two distinct patterns of Ca(2+)-mediated activation of Ca(2+)-ATPase were identified in calmodulin-depleted membranes. 2. In membranes showing no activation (type A), preincubation with micromolar concentration of cyclic AMP and ATP made possible stimulation of the enzyme while in membranes already exhibiting activation (type B), preincubation with cyclic AMP and ATP abolished the activation. 3. ATPase stimulation in type A membranes was suppressible by leupeptin. 4. Triton extractable inhibitor isolated from type A membranes was as active as that derived from type B membranes only after preincubating the membranes with cyclic AMP and ATP. 5. The inhibitor could be inactivated by alkaline phosphatase.
...
PMID:Variations in Ca(2+)-mediated activation of Ca(2+)-ATPase and its associated inhibitor in erythrocyte membrane. 132 91

The effects of tissue maturation on the cellular composition and biochemical characteristics of bone were studied in neonatal, young adult, and aging mice. Osteoblast subclasses were isolated on Percoll density gradients. Neonatal calvariae consisted almost exclusively of cells banding at low and intermediate buoyant density. High buoyant density cells constituted 5-10% of total cells at 10 days of age but increased to 50-60% by 5 weeks of age. These latter cells were released late during collagenase digestion. This indicates that they arise from the deeper layer of bone. For this reason, we consider them putative osteocytes. We established that constitutive secretion of IGF-I and TGF-beta and activities of cellular alkaline phosphatase paralleled those of the tissue of origin in all cell groups and was highest in cells of intermediate buoyant density. These activities declined rapidly after cessation of growth at 5 weeks of age in both bone and isolated cells. Between 5 and 8 weeks of age, the hormonal response to PTH also declined dramatically. The maximum cAMP induced by PTH declined by about 70% in highly responsive cells of intermediate buoyant density and fell to insignificant levels in cells of high buoyant density. We found that a cyclic AMP response to PTH was positively correlated with stimulated secretion of IGF-I by this hormone in cells from animals of all ages. Despite their inability to respond to PTH with increases in cAMP and IGF-I, adult bone cells of high buoyant density continued to respond to PTH with increases in the secretion of TGF-beta.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Maturation-associated changes in the cellular composition of mouse calvariae and in the biochemical characteristics of calvarial cells separated into subclasses on Percoll density gradients. 132 39

Electrophysiological studies have shown that the olfactory organ (antennule) of the spiny lobster, Panulirus argus, has chemoreceptors that are selectively excited by adenine nucleotides in seawater. Biochemical studies have revealed that these same nucleotides can be rapidly dephosphorylated by ectoenzymes associated with the olfactory sensilla (aesthetascs). In this study the distribution of ecto-ATPase/phosphatase activity within aesthetascs was determined cytochemically and the nature of the adenine-nucleotide dephosphorylating activity was dissected biochemically. Cytochemically, the distribution of ATP-dephosphorylating activity was similar to that shown previously for AMP and beta-glycerol phosphate; i.e., cerium phosphate reaction product was specifically localized to the transitional zone where the sensory dendrites develop cilia and branch to form the outer dendritic segments. Unlike the dephosphorylation of AMP and beta-glycerol phosphate, Mg2+ or Ca2+ was required for ecto-ATPase/phosphatase activity. Biochemical measures of both AMP- and ATP-dephosphorylating activity within aesthetascs corroborated the cytochemical evidence that these activities are localized to the transitional zone. A major portion of the AMP dephosphorylation (about 67%) derives from nonspecific alkaline phosphatase activity that is insensitive to levamisole and L-bromotetramisole. In contrast, nonspecific phosphatase activity accounted for a much smaller part of the ATP dephosphorylation (about 15%). Ectoenzymatic activity in the transitional zone may be an important means of removing excitatory/inhibitory nucleotides from this region.
...
PMID:Ecto-ATPase/phosphatase activity in the olfactory sensilla of the spiny lobster, Panulirus argus: localization and characterization. 133 Mar 15

In antrectomized (B-I) and control rats, bone mineralization, the fractional intestinal absorption of calcium, magnesium and phosphorus, the balances of these minerals, their serum concentration and renal excretion, together with serum gastrin, calciotropic hormones (parathyroid hormone, calcitonin, 1,25-dihydroxyvitamin D), and osteocalcin were assessed four months after surgery. B-I evoked hypogastrinemia, but no changes in the serum concentrations of minerals and calciotropic hormones, or urinary cyclic AMP. The major significant changes brought about by B-I were: (1) a decrease in bone dry weight, specific density, bone ash calcium and magnesium content; (2) a decrease in the fractional absorption and urinary excretion of calcium and magnesium; (3) an increase in urinary hydroxyproline and serum osteocalcin in the presence of normal serum bone isoenzyme of alkaline phosphatase. It is concluded that in the rat (1) B-I over the long term decreases both bone mineral content and calcium and magnesium absorption, in the absence of any counterregulation; (2) B-I rats may have attained a new equilibrium which is characterized by decreased absorption and urinary excretion of calcium and magnesium, but maintenance of normocalcemia at the expense of bone; (3) the concomitant changes of serum bone markers are contradictory, which makes their interpretation and use in the present context difficult.
...
PMID:Disturbances of mineral and bone metabolism following gastric antrectomy in the rat. 133 20

The use of intestinal segments in the urinary tract can cause metabolic changes that depend on the intestinal segment utilized. The severity of these changes basically depends on the area of the intestinal mucosa in contact with urine, the duration of exposure to urine and renal function. The length of time the intestinal mucosa is in contact with urine largely depends on the surgical technique employed. It is longer for the reservoirs, intestinal neobladders and ureterosigmoidostomies than for the intestinal conduits with cutaneous urinary diversion and therefore carry a higher incidence of metabolic changes. Jejunal urinary diversion causes metabolic acidosis with hypochloremia, hyponatremia, hyperpotassemia, azotemia and dehydration in at least 50% of the cases. Ileal and colonic urinary diversion can cause metabolic acidosis, although the incidence is significantly less. Acidosis presents with hyperchloremia, hyperammonemia, hypersulfatemia, increased osmolality and uremia with normal creatininemia and a tendency to develop hypocalcemia, hypophosphoremia and hypomagnesemia. Recent studies performed in our service show that acidosis is basically due to the secretion of sodium bicarbonate by the intestinal segment used in the urinary tract, which causes water-salt depletion that is compensated by secondary hyperaldosteronism. Mild chronic acidosis is neutralized via the respiratory system and by the bone buffers, which leads to bone remodelling manifested by the significant increase of serum alkaline phosphatase levels and increased calciuria. These calcium phosphate changes, although statistically significant, do not appear to be important since they were not accompanied by changes of serum PTH levels, 25 and 1-25-cholecalciferol. Nicotinic acid as inhibitor of cyclic AMP synthesis failed to correct metabolic acidosis in the patients with transileal diversion.
...
PMID:[Physiopathology and treatment of metabolic changes in transintestinal urinary diversions]. 133 44


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---