Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously have shown that aging alters the expression of several intestinal enzymes during cell migration from the crypt base to the villus tip. The activities of many mucosal enzymes are dramatically altered by starvation and refeeding. We compared the effects of starvation and refeeding on the activities of selected intestinal enzymes in young and aging Fischer 344 rats. Gut mass fell during starvation and rose during refeeding to a similar extent in both groups. Sucrase and maltase specific activities in control aging rats were lower than in young controls and, during starvation, enzyme activities declined at approximately similar rates in both groups. Total duodenal enzyme activities fell by about two-thirds in young animals and by greater than 80% in aged animals. Alkaline phosphatase and adenosine deaminase activities also were lower in aging than young animals. During refeeding, enzyme activities rose more in aging rats than in the young. In fact, the specific activities of sucrase and maltase in aging rats refed for 1 day exceeded the values found in fed aging controls. The adaptive responses of duodenal enzymes exceeded those in the jejunum. In conclusion, the aging intestine responds appropriately to starvation and refeeding. However, the fluctuations in brush-border enzyme activities are much greater in aging than in young rats. Such alterations may be an important influence of aging on gut differentiation and might have an adverse impact upon nutritional maintenance in aging animals.
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PMID:Adaptive changes of intestinal enzymes to nutritional intake in the aging rat. 359 66

To evaluate the effect of aging upon the small intestine, the distribution, content, and concentration of epithelial cell enzymes at different levels along the crypt-villus column were measured in aging and young adult, male, Fisher 344 rats. Specific activities of sucrase, maltase, lactase, and adenosine deaminase in mucosal homogenates were lower in the upper intestines of aging than in young animals, whereas the specific activity and content of thymidine kinase was higher. Enzyme activities were measured in cells obtained by cryostat sectioning from villus tip to crypt base. Sucrase and maltase activities were fully expressed nearest the crypt, alkaline phosphatase in cells higher on the villus, and adenosine deaminase higher still, whereas thymidine kinase activity was limited to the crypts. The ordered pattern of enzyme expression was maintained in aging rats but the initiation and duration were delayed. Because peak specific enzyme activities were similar in young and aging animals, the reduced specific activities in mucosal homogenates from aging animals were due to an increase in the proportion of relatively undifferentiated villus epithelial cells. These findings are of importance in explaining altered intestinal function during aging without a concomitant change in intestinal structure.
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PMID:Delayed enzyme expression: a defect of aging rat gut. 393 Mar 40

Ten enzymes, all known to be glycoproteins, were examined by electrophoresis or gel isoelectric focusing in 12 different patients with primary or secondary sialidase deficiency. Aberrant electrophoretic mobilities of many of the enzymes attributable to abnormal sialylation were found in all the patients. In ten of the patients seven of the enzymes were affected. The unaffected enzymes were beta-galactosidase, alkaline phosphatase and beta-glucuronidase. In the cells from the two patients with I cell disease (mucolipidosis II) in which sialidase is one of many deficient enzymes, beta-galactosidase, alpha-galactosidase, alpha-fucosidase and alpha-mannosidase were undetectable, alkaline phosphatase showed a normal electrophoretic mobility and acid phosphatase, adenosine deaminase, alpha-glucosidase and beta-D-N-acetylhexosaminidase showed aberrant mobilities.
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PMID:Electrophoretic analysis of glycoprotein enzymes in the sialidoses and mucolipidoses. 645 53