Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The common hookworm (Ancylostoma ceylanicum) infection of humans was studied in golden hamsters model system. Significant biochemical modulations were observed in hamster jejunal brush border membrane (BBM), the primary site of infection. Analysis of BBM at the peak of infection (3-weeks) revealed a marked decrease in the activities of sucrase, lactase and maltase, while activities of alkaline phosphatase, (Ca2+ + Mg2+)-ATPase and gamma-glutamyl transpeptidase were increased. Kinetic studies conducted with maltase, a superficially localised enzyme of jejunal BBM, revealed loss of enzyme active site during the infection. Among other constituents, the levels of cholesterol and triglycerides were significantly decreased with slight increase in phospholipid content in the infected animals. The hookworm infection also caused a decline in total hexose content indicating an altered membrane glycocalyx. Conversely, there was significant enhancement of hydroxyproline and sialic acid contents. SDS-PAGE analysis showed an enhancement in both low and high molecular weight proteins in jejunal BBM preparations of the infected group. Gel electrophoresis of glycoproteins further revealed the appearance of two additional peaks in the low molecular weight region and concomitant disappearance of a peak in the high molecular weight region. These results strongly support the view that the hookworm infection causes severe damage not to the site of attachment alone but also to the entire cell lining of the jejunum and therefore could influence overall digestion and absorption.
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PMID:Biochemical analysis of jejunal brush border membrane of golden hamster: pathogenic modulations due to ancylostomiasis. 159 19

The thermodynamics of 10 industrially-important, enzyme-catalyzed reactions are examined. The reactions discussed are: the conversions of penicillin G to 6-amino-penicillinic acid using the enzyme penicillin acylase; starch to glucose using amylases; glucose to fructose using glucose (xylose) isomerase; cellulose to glucose using cellulase; fumaric acid and ammonia to L-aspartic acid using L-aspartase; transcinnamic acid and ammonia to L-phenylalanine using L-phenylalanine ammonia lyase; L-histidine to urocanic acid and ammonia using L-histidine ammonia lyase; lactose to glucose and galactose using lactase; and the reactions catalyzed by amino acylases and proteases. The selection of these processes was based on the economic value of the products and their intrinsic industrial importance. The available thermodynamic properties, such as equilibrium constants, Gibbs energies (delta G degrees), enthalphies (delta H degrees), and heat capacity changes (delta Cp degrees) of these enzyme-catalyzed reactions, are reviewed and summarized. Recommendations are made for future research in this area.
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PMID:Thermodynamics of industrially-important, enzyme-catalyzed reactions. 169 84

Factors, such as insulin, found in human and pig colostrum and mature milk likely influence small intestinal growth and development. Although pharmacologic doses of insulin injected parenterally may accelerate small intestinal development in altricial animals such as the rodent, the effects of oral insulin on intestinal development have not been studied. In the first of two studies, we randomized 2-d-old miniature piglets to receive bottle-feedings of a swine weaning milk formula with (group F + I) or without (group F) the addition of insulin. Serum glucose, insulin, and cortisol were measured before and 1 h after the first feeding the piglets received at our facility. In the second study, piglets were randomized (groups F and F + I) and fed for 6 d, after which blood samples were obtained as in the first experiment. The piglets were then killed and the small intestine removed for analysis. We found no differences between groups in serum glucose, insulin, and cortisol at both 2 and 8 d of age, both before and after feeding. In the second experiment, small intestinal weight was greater in the F + I than in the F group. Although no differences were noted between groups in the jejunum, values were greater for group F + I versus group F for ileal mucosal weight, protein, RNA, lactase, and maltase activities. No differences were found between groups in ileal DNA or sucrase activity. We conclude that the administration of oral insulin stimulated an increase in ileal mass and disaccharidase activity in the newborn miniature pig without apparent concomitant changes in serum glucose, insulin, or cortisol.
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PMID:Oral insulin increases small intestinal mass and disaccharidase activity in the newborn miniature pig. 169 70

Rotavirus enteritis is the leading cause of diarrhea in infants worldwide. A research priority of the World Health Organization is to develop oral rehydration solutions containing amino acids or other additives that will stimulate intestinal absorption more efficiently than the current glucose-based oral rehydration solutions. Glutamine is the principal metabolic fuel of the small bowel and a putative stimulator of mucosal repair. This report describes the transport response to mucosal L-glutamine following intestinal injury caused by porcine rotavirus. Peak symptoms and mucosal damage were observed 2-7 days after oral rotavirus inoculation. In vitro transport studies of the maximally injured region, the midjejunum (80% reduction in lactase), surprisingly, showed transport responses to L-glutamine (30 mmol/L) and L-alanine (30 mmol/L) that were similar qualitatively and quantitatively to those observed in control tissue. Subsequent application of mucosal D-glucose (30 mmol/L) caused additional stimulation of electrogenic Na+ transport, but the response to glucose was blunted (P less than 0.05) in the infected tissues. Glutamine and alanine enhanced Na+ absorption to a similar degree (2-2.5 muEq.cm-2.h-1), but glutamine stimulated equal amounts of electrogenic and electroneutral NaCl absorption, whereas alanine had no significant effect on net Cl- flux. Glutamine is a potentially useful substrate for investigation in oral rehydration solutions for infant diarrhea.
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PMID:L-glutamine stimulates jejunal sodium and chloride absorption in pig rotavirus enteritis. 188 9

1. The metabolic consequences of chronic ethanol feeding was investigated by assay of urinary metabolites. Male Wistar rats were fed a liquid diet containing 35% of total energy as ethanol or isovolumetric, isocaloric and isonitrogenous amounts of the same diet in which ethanol was substituted by isocaloric glucose (controls). 2. At 6 weeks the entire skeletal muscle mass was reduced by approximately 20%. The urinary excretion of nitrogen, urea and uric acid increased by between 23 and 128%. Urinary creatinine excretion was not significantly altered. 3. Urinary excretion of magnesium was significantly increased by 43%. Urinary excretion of sodium, potassium, calcium and phosphate was increased slightly (i.e. 5-22%), but this change was not statistically significant. 4. Proton n.m.r. spectroscopic analysis showed that ethanol feeding reduced the urinary excretion of citrate and 2-oxoglutarate (by approximately 50%), suggesting decreased citric acid cycle activity. There was an increased excretion of alanine (44%), but excretion of succinate and acetate was not significantly altered. Ethanol in the urine of ethanol-fed rats comprised approximately 2% of total ethanol intake and less than 1% of total energy intake. 5. Lactose was detectable in urine of ethanol-fed rats, but not in control rats, reflecting the reported decreased intestinal lactase activity and increased gut permeability in alcoholics. Urinary galactose excretion decreased by 41%, but relatively large increases in lactate excretion (50%) did not achieve statistical significance. 6. It was concluded that chronic ethanol feeding causes disturbances in whole-body nitrogen homoeostasis and alterations in intermediary metabolism.
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PMID:Urinary excretion of nitrogenous and non-nitrogenous compounds in the chronic ethanol-fed rat. 185 Oct 76

Lactose-intolerant postweaning rats were fed experimental diets including yogurt, quargs prepared from yogurt culture and buttermilk culture, and two types of whey obtained from quarg processing. After feeding each diet for a period of 7 d, absence of blood glucose elevation and occurrence of diarrhea were used as indicators of lactose malabsorption. Blood glucose assays and absence of diarrhea indicated that yogurt and quargs prepared from yogurt and buttermilk culture were well tolerated by the rats. Wheys containing the same levels of viable organisms and lactose as the quargs caused severe symptoms of diarrhea and poor lactose absorption as indicated by no changes in blood glucose levels. Plate counts and enzyme assays of gastrointestinal contents confirmed presence of viable culture organisms and beta-galactosidase activity after feeding the two types of quarg. The availability of viable organisms, the exogenous lactase activity, and especially the slow gastric emptying may all have contributed to more efficient hydrolysis and digestion of lactose from quargs and yogurt than from the wheys.
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PMID:Lactose absorption by postweaning rats from yogurt, quarg, and quarg whey. 190 66

1. Change in digestive enzyme activities determined biochemically in brush-border membrane vesicles and cytochemically in isolated villi of lamb proximal intestine has been related to diet, intestinal structure and rumen development during the first 10 weeks of postnatal life. 2. Lactase activity halved, dipeptidylpeptidase IV activity doubled and aminopeptidase N and alkaline phosphatase activities remained constant during this period of development. Maintaining lambs on a milk replacer diet for 5 weeks after birth had no effect on this pattern of postnatal change in digestive enzyme activities. 3. Structural changes accompanying these selective effects on enzyme expression included a halving of villus height and a doubling of villus width. Villus surface area remained unaffected by these changes in height and width of villi. Crypt depth doubled during the first 10 weeks of postnatal life. Maintaining lambs on a milk replacer diet for 5 weeks did not affect this pattern of change in intestinal structure. 4. It appears from these results that postnatal decrease in lactase and increase in dipeptidylpeptidase IV activities are not regulated by factors such as diet, rumen development, or changes in intestinal structure. Attention is drawn to differences encountered between these results and a postnatal modification of glucose transport which clearly is dependent on diet.
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PMID:Postnatal development of lamb intestinal digestive enzymes is not regulated by diet. 190 59

Total parenteral nutrition (TPN) decreases disaccharidase activity in the small intestine of humans and miniature piglets. The possibility, however, that specific components of TPN (eg, the energy mix) will increase disaccharidase activity has largely been unexplored. The identification of such components would be particularly useful in the treatment of premature infants with immature gastrointestinal tracts and patients with small intestinal mucosal disease associated with decreased disaccharidase activity. To determine whether the TPN energy composition affects small intestinal disaccharidase activity, 7-day-old miniature piglet littermates were randomized to receive TPN containing either glucose (group G) or glucose and fat (group G/F) as the nonnitrogen energy source(s). The TPN regimens were isonitrogenous and isoenergetic. The piglets were not allowed oral intake during the 7 days they were maintained on TPN. At 14 days of age the piglets were killed and the small intestines analyzed for weight, protein, DNA, and disaccharidase activity. Body weight was similar between groups at both the beginning and end of the study. The TPN regimen did not affect small intestinal weight of protein and DNA content. However, jejunal and ileal sucrase and ileal maltase activities (mumol/min.kg body wt +/- SD) were greater in group G than those in group G/F (28 +/- 9 vs 19 +/- 11, p = 0.04; 13 +/- 7 vs 7 +/- 4, p = 0.037; and 31 +/- 8 vs 19 +/- 10, p = 0.0088, respectively). No differences in lactase activity were noted between groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Total parenteral nutrition energy composition affects small intestinal disaccharidase activity in the newborn miniature pig. 194 71

The purpose of this investigation was to determine if the presence of carbohydrate in milk, either lactose or its hydrolysis products, enhance the bioavailability of calcium (Ca) in milk. Two studies were performed. In study A, fractional Ca absorption was measured in 11 lactose-tolerant postmenopausal women after an oral dose of 47Ca-equilibrated milk formula containing no carbohydrate (NOCHO), lactose (LACTOSE), or an equivalent amount of glucose plus galactose (SUGAR); all participated in three absorption studies in random order. The NOCHO formula contained 10.0 g protein and 217 mg Ca from a combination of milk mineral and protein isolates; the LACTOSE and SUGAR formulae contained in addition 12 g lactose or 6 g glucose plus 6 g galactose, respectively. In study B, fractional Ca absorption was measured in five postmenopausal women after an oral dose of 47Ca-equilibrated skim milk (217 mg Ca) and lactase-treated milk, each with sufficient carbohydrate added to equal 12 g. For both studies, the increase in forearm radioactivity 4 and 8 hours after oral 47Ca administration relative to the increase observed after IV administration was used to estimate fractional Ca absorption. The addition of lactose but not glucose plus galactose to the NOCHO formula enhanced Ca absorption (p less than 0.05). Fractional absorption at 4 hours was 0.386 from the LACTOSE formula compared with 0.310 for both the NOCHO and SUGAR formulae. Those individuals with the lowest absorption in the absence of carbohydrate had the greatest increase with lactose. In contrast, Ca absorption was the same from skim milk as from lactase-treated skim milk (study B).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of carbohydrates in milk on the absorption of calcium by postmenopausal women. 203 Feb 55

Brush border lactase, sucrase and glucoamylase activities were assessed in jejunal mucosal biopsy specimens from 34 children (median age 11 months; range 1.5-38) having protracted diarrhoea with failure to thrive and 8 well nourished children with normal jejunal mucosal histology (median age 10.2 months; range 2-37). All enzymes showed progressive decrease in activity which was directly in relation to increasing degree of mucosal injury (P less than 0.002). Lactase was significantly reduced even in patients with protracted diarrhoea and normal mucosa (P less than 0.05). Glucoamylase and sucrase were significantly reduced only in the presence of mucosal injury (P less than 0.01). Our data suggest that most children with protracted diarrhoea may not tolerate lactose containing feeds and may need lactose-free diets preferably based on starch. A small number of children with protracted diarrhoea, who have severe mucosal injury may not be able to handle even starch and may require diets based on short chain glucose polymers. The findings of this study, need to be corroborated with well-controlled metabolic balance studies.
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PMID:Intestinal glucoamylase & other disaccharidases in children with protracted diarrhoea. 211 15


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