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)

Quercitrin (3-rhamnosylquercetin) is a bioflavonoid contained in several crude drugs traditionally used for its antidiarrhoeal activity. The antidiarrhoeic effect of quercitrin on experimental chronic diarrhoea in rats was studied. Adult rats were fed for 14 days with a synthetic diet in which all soluble carbohydrates were substituted by lactose, resulting in chronic diarrhoea with body weight loss, colonic hyperplasia, reduced average cell size, increased alkaline phosphatase activity, increased mucus production and cytopathological alterations of the enterocyte. The rest of the animals were allowed to recover from chronic diarrhoea for 3 or 7 days, by feeding them with a standard diet, and half of them were also given quercitrin orally (50 mg/kg day). Diarrhoea ceased 48 h after lactose withdrawal, and body weight recovery was apparent after 3 days. Nevertheless, most of the alterations of the colonic mucosa persisted at that time. Quercitrin-treated rats had less diarrhoeal output and did not show mucosal hyperplasia after three days of treatment. All animals had greatly recovered by the seventh day, but histological alterations were still present, although to a lesser extent in quercitrin-treated rats. Quercitrin and related flavonoids may play a role in intestinal repair following chronic mucosal injury.
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PMID:Effect of quercitrin on lactose-induced chronic diarrhoea in rats. 748 Jan 74

The use of lactose permease-alkaline phosphatase fusions (lacY-phoA) demonstrates that the lactose permease of Escherichia coli contains 12 transmembrane domains and that approximately half of a transmembrane domain is required to translocate alkaline phosphatase to the periplasmic surface of the membrane [Calamia, J., & Manoil, C. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 4937-4941]. We have now used fusion analysis in combination with site-directed spectroscopy to examine more precisely the topology of putative helices VII and XI which contain the interacting residues Asp237 and Lys358, respectively. For this purpose, alkaline phosphatase was fused to alternate amino acid residues in transmembrane domains VII and XI. A sharp increase in alkaline phosphatase activity is observed as the fusion junction proceeds from Try228 to Ile230 in helix VII and from Phe354 to Phe356 in helix XI, suggesting that these residues approximate the middle of the corresponding transmembrane helices. Analysis of fluorescence quenching of the pyrene-labeled single-Cys mutants Asp237 --> Cys or Lys358 --> Cys, as well as measurement of collision frequencies between freely diffusing paramagnetic probes and a nitroxide spin-label at these sites, also indicates that Asp237 and also Asp240, which interacts with Lys319 (helix X), are located in transmembrane domains. However, Asp237 and Asp240 are accessible both from the aqueous phase and from within the membrane. The results provide more direct evidence that the three residues are located within transmembrane helices and suggest that Asp237 and Asp240 are either located near the periplasmic surface of the membrane or exposed within a solvent-filled cleft in the permease.
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PMID:Membrane topology of helices VII and XI in the lactose permease of Escherichia coli studied by lacY-phoA fusion analysis and site-directed spectroscopy. 757 3

Feeding lactose or other slowly digestible carbohydrates to adult mammals may induce a variety of effects including hyperplasia and neoplasia. The most fundamental effect probably is the increased production in the large intestine of short-chain fatty acids (SCFA) resulting from increased fermentation of carbohydrate residues. To find out whether the increased production of these acidic compounds is involved in the induction of certain alterations caused by low-digestibility carbohydrates, the modifying effects of an acidifying (NH4Cl) or an alkalizing (KHCO3) diet supplement on lactose-induced changes in rats were studied. Three groups of 50 rats per sex were fed a 20% lactose diet unsupplemented or supplemented with 1% NH4Cl or 2% KHCO3, for at most 2.5 yr. One control group was fed the basal diet which contained wheat starch instead of lactose. Feeding lactose resulted in wet faecal pellets, reduced pH of the faeces, higher intake of food and water, lower body weights, increased caecal weights and fewer deaths. These effects were not significantly modified by NH4Cl or KHCO3. Feeding lactose increased urinary calcium levels, the effect being enhanced by NH4Cl and reduced by KHCO3. Lactose also tended to increase blood values of alkaline phosphatase and to decrease those for bicarbonate and base excess. These tendencies were generally more marked with NH4Cl, and less marked or absent with KHCO3. In addition, rats fed lactose showed decreased severity of nephrosis, increased mineralization and hyperplasia of the renal pelvic epithelium, and relatively high incidences of Leydig cell hyperplasia and neoplasia. NH4Cl supplementation was associated with a relatively small number of single and multiple tumours, with decreased incidences of hyperplasia and mineralization of the renal pelvis epithelium and with a markedly reduced incidence of proliferative changes in the adrenal medulla. With the KHCO3 supplement the incidences of Leydig cell proliferation and of bladder tumours were relatively high. These findings, in particular the differences between the diet groups in urinary calcium levels and possibly also the variations in blood levels of alkaline phosphatase, bicarbonate and base excess, suggest that the acidic end products of carbohydrate fermentation (SCFA) act as an acid load on the body.
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PMID:Effects of a dietary load of acid or base on changes induced by lactose in rats. 782 70

The lactose permease (lac) of Escherichia coli is a paradigm for membrane transport proteins. Encoded by the lacY gene, the permease has been solubilized, purified to homogeneity, reconstituted into phospholipid vesicles and shown to catalyse the coupled translocation of beta-galactosides and H+ with a stoichiometry of unity. Circular dichroism and other spectroscopic approaches demonstrate that the purified permease is about 80% helical. Based on hydropathy analysis of the primary amino-acid sequence, a secondary structure has been proposed in which the protein has 12 hydrophobic domains in alpha-helical conformation that traverse the membrane in zigzag fashion connected by hydrophilic loops. A variety of other approaches are consistent with the model and demonstrate that both the N and C termini are on the inner surface of the membrane, and studies on an extensive series of lac permease/alkaline phosphatase fusion proteins provide exclusive support for the topological predictions of the 12-helix motif. This presentation concentrates on the use of site-directed fluorescence spectroscopy to study structure-function relationships in the permease.
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PMID:The lactose permease meets Frankenstein. 782 21

The lactose permease of Escherichia coli has 12 transmembrane hydrophobic domains in probable alpha-helical conformation connected by hydrophilic loops. Previous studies [Consler, T. G., Persson, B., et al. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 6934-6938] demonstrate that a peptide fragment (the XB domain) containing a factor Xa protease site immediately upstream of a biotin acceptor domain can be engineered into the permease, thereby allowing rapid purification to a high state of purity. Here we describe the use of the XB domain to probe topology and insertion. Cells expressing permease with the XB domain at the N terminus, at the C terminus, or in loop 6 or 10 on the cytoplasmic face of the membrane catalyze active transport, although only the chimeras with the XB domain at the C terminus or in loop 6 are biotinylated. In contrast, chimeras with the XB domain in periplasmic loop 3 or 7 are inactive, but strikingly, both constructs are biotinylated. Furthermore, the XB domain in all the constructs, particularly in the loop 3 and loop 7 chimeras, is accessible from the cytoplasmic face of the membrane, as evidenced by factor Xa proteolysis or avidin binding studies with spheroplasts and disrupted membrane preparations. Finally, alkaline phosphatase fusions one loop downstream from each periplasmic XB domain exhibit high phosphatase activity. Thus, the presence of the XB domain in a periplasmic loop apparently blocks translocation of a discrete segment of the permease consisting of the loop and the two adjoining helices without altering insertion of the remainder of the protein.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Insertion of the polytopic membrane protein lactose permease occurs by multiple mechanisms. 788 Aug 37

Numerous osteometabolic factors are implicated in the bone mass loss which occurs with ageing. Among these a significant role is played by the impairment of intestinal calcium absorption which may be attributed in the elderly to various factors such as the reduction of chlorhydro-peptic secretion, the correlated deficiency of vitamin D and their relative duodenal receptors. In order to evaluate the clinical efficacy of an arginine-lysine-lactose preparation a group of 40 subjects with senile involutional osteoporosis was studied. The subjects were divided into two groups using random criteria and were treated with carbocalcitonin alone (40 UMRC day i.m. on alternative days) or carbocalcitonin association complex. The following parameters were evaluated in basal conditions and after six months of treatment: bone mass density (BMD) using computerised bone mineralometry, bone pain, intake of analgesics, serum levels of calcium, phosphorus, alkaline phosphatase, osteocalcin, parathormone, as well as calciuria and hydroxyprolinuria. The comparison between the two groups shows a more marked increment in BMD in subjects treated with arginine-lysine-lactose, a greater reduction in painful symptoms, and a more evident and significant reduction of parathormone and hydroxyprolinuria levels. These effects appear to be due to a distinct improvement in intestinal calcium absorption mediated by lysine and lactose, and probably to a positive action played by the amino acid at the level of support structures.
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PMID:[The effects of the carbocalcitonin + arginine-lysine-lactose combination in senile involutional osteoporosis]. 802 55

Two matched groups of postmenopausal patients were treated respectively with calcitonin or calcitonin and an arginine-lysine-glycerophosphoric acid-lactose association. The rationale underlying this therapy took the form of data in the literature which indicated an action of these amino acids and lactose on calcium absorption and on the metabolism of protein components in the skeletal structure. The following tests were performed: mineralometric evaluation, evaluation of painful symptoms and intake of pain-relieving drugs, serum levels of calcium, phosphorus, alkaline phosphatase, osteocalcin, parathormone, and calciuria and hydroxyproline. These parameters were assayed at the beginning and end of treatment which lasted six months. The results, or in other words the comparison between the two groups, basal or after treatment, and the values recorded before and after treatment in each group, enable the authors to affirm that the administration of the arginine-lysine-glycerophosphoric acid-lactose association leads to an increase in bone density and plasma osteocalcin, a reduction in painful symptoms and analgesic intake, and a reduction in the serum levels of parathromone and hydroxyproline. Data reported in the literature support the conclusion that the results obtained are the consequence of an improved intestinal absorption calcium. It is highly probable that the protein components of the association administered, arginine-lysine-glycerophosphoric acid-lactose, also exercise a direct action on osteoblasts and on the metabolism of bone matrix protein components.
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PMID:[Experience regarding the use of arginine-lysine-lactose treatment in menopausal osteoporosis]. 808 36

Alkaline phosphatase was used as a model in studies to assess the effects of lyophilization on biological activity and molecular integrity in the presence or absence of added carbohydrate. The stability of the activity of alkaline phosphatase, lyophilized in Tris buffer alone or in the presence of the carbohydrates mannitol, lactose or trehalose was examined. Enzyme activity in formulations with Tris buffer alone or with mannitol was considerably reduced by freeze-drying and further storage at elevated temperatures; freeze-drying with mannitol failed to maintain activity at a temperature of 37 degrees C over 21 days, whilst the loss of activity was more gradual when freeze-dried in buffer alone and stored at higher temperatures. Lactose and trehalose maintained the alkaline phosphatase activity after freeze-drying and, furthermore, preparations containing trehalose retained activity even when the material was subjected to temperatures of up to 45 degrees C for up to 84 days. At 56 degrees C the alkaline phosphatase activity did not show a significant drop until 14 days with the lactose formulation or until 21 days with trehalose. After 84 days at 56 degrees C, 30% of the activity still remained in the formulation containing trehalose. In addition to the changes in the enzyme activity, FPLC chromatographic traces and SDS-PAGE gels demonstrated compositional differences between each formulation after storage.
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PMID:The effect of carbohydrate additives in the freeze-drying of alkaline phosphatase. 809 38

A new approach to facilitate immobilization and affinity purification of recombinant proteins and selected human B lymphocytes has been developed. Using magnetic beads with attached DNA containing the Escherichia coli lac operator, fusion proteins comprising the DNA-binding lac repressor could be affinity-purified and recovered by gentle elution conditions, such as with a lactose analogue or by enzymatic means using either deoxyribonuclease (DNase) or restriction endonucleases. The results show for the first time that a DNA-binding protein can be used for affinity purification of fusion proteins as exemplified by the specific and gentle recovery of beta-galactosidase and alkaline phosphatase from bacterial lysates using immunomagnetic separation. The approach was further extended to cell separation by the efficient recovery and elution of human CD37 B lymphocytes from peripheral blood.
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PMID:Immobilization and recovery of fusion proteins and B-lymphocyte cells using magnetic separation. 847 Nov 67

Raw cows' and goats' milks were heated by microwave in a continuous flow unit up to temperatures ranging from 73.1 to 96.7 degrees C. The effects of the heat treatments were estimated by measurements of lactose isomerization, protein denaturation, inactivation of alkaline phosphatase and peroxidase and the total bacterial count. Negative phosphatase tests and low bacterial counts, together with low degrees of whey protein denaturation, were achieved under several temperature/time combinations. The results indicate that continuous microwave processing may be an efficient and mild approach for the pasteurization of milk.
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PMID:Effects of continuous flow microwave treatment on chemical and microbiological characteristics of milk. 871 91


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