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)

1. A low protein diet prevents the development of proteinuria and glomerular damage in adriamycin experimental nephrosis without affecting renal haemodynamics. In this study the hypothesis was tested as to whether protein restriction is able to modulate the purine metabolic cycle and related enzymes such as xanthine oxidase, one of the putative effectors of adriamycin nephrotoxicity. 2. Renal activities of xanthine oxidase and purine nucleoside phosphorylase were markedly depressed in adriamycin-treated rats fed a 9% casein (low protein) diet compared with the group fed a 22% casein (normal protein) diet both 1 day after adriamycin administration and at the time of appearance of heavy proteinuria (day 15), whereas the activity of renal adenosine deaminase was unchanged. 3. The concentrations of the metabolic substrates of xanthine oxidase, i.e. hypoxanthine and xanthine, were constantly lower in renal homogenates of rats fed a low protein diet compared with those on a normal protein diet. In urine, uric acid, the product of hypoxanthine-xanthine transformation, was lower 1 day after adriamycin injection in protein-restricted rats compared with the group on a normal protein diet which showed a marked increase in its excretion. At the same time, the urinary efflux of adenosine 5'-monophosphate, which is the precursor nucleotide of the above-mentioned nucleosides and bases, was very high in rats fed a low protein diet, whereas it was absent in the group on a normal protein diet. 4. The progressive increment in proteinuria of glomerular origin (i.e. increased excretion of albumin and transferrin) typical of adriamycin-treated rats fed a normal protein diet was inhibited in the protein-restricted animals, which were normoproteinuric on day 10 and were only slightly proteinuric on day 15. 5. Like protein restriction, the pharmacological suppression of renal xanthine oxidase by dietary tungstate and the scavenging by dimethylthiourea of the putative free radical deriving from the action of xanthine oxidase, were associated with a similar (quantitative and qualitative) inhibition of glomerular proteinuria. 6. These data demonstrate that dietary protein restriction is associated with a block in purine metabolism within the kidney due to a marked reduction in the activities of two main enzymes of the cycle, i.e. purine nucleoside phosphorylase and xanthine oxidase, the latter being a putative effector of adriamycin nephrotoxicity. The partial reduction of proteinuria induced by a low protein diet is quantitatively and qualitatively comparable with the reduction induced by the specific block of renal xanthine oxidase or by the scavenging of OH.deriving from hypoxanthine and xanthine transformation.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Effect of dietary protein restriction on renal purines and purine-metabolizing enzymes in adriamycin nephrosis in rats: a mechanism for protection against acute proteinuria involving xanthine oxidase inhibition. 217 53

In the present study adenosine deaminase (ADA) was immobilized onto two different polymeric materials, agarose and casein. The factors affecting the amount of enzyme attachment onto the polymeric supports such as incubation time were investigated. The maximum amount of enzyme immobilized onto different polymeric supports occurred at incubation pH value 7.5 and ADA concentration 42 units/g and the incubation time needed for the maximum amount of enzyme attachment to the polymeric supports was found to be 8 h. Some phsicochemical properties of the free and immobilized ADA such as operational stability, optimum temperature and thermal stability, pH optimum and stability, storage stability, and the effect of gamma-radiation were studied. The operational stability of the free and immobilized enzyme showed that the enzyme immobilized by a cross-linking technique using gultaric dialdehyde showed poor durability and the relative activity decreased sharply due to the leakage after repeated washing, while the enzymes immobilized by covalent bonds to the carriers showed a slight decrease in most cases in the relative activity (around 20%) after being used 10 times. Storage for 4-6 months, showed that the free enzyme lost its activity, while the immobilized enzyme showed the opposite behavior. Subjecting the immobilized enzyme to a dose of gamma radiation of 0.5-10 Mrad showed complete loss in the activity of the free enzyme at a dose of 5 Mrad, while the immobilized enzymes showed relatively high resistance to gamma radiation up to a dose of 5 Mrad.
 ...
PMID:Immobilization of adenosine deaminase onto agarose and casein. 1200 11