Brain guanine deaminase: Purification, properties and regional distribution

Mansoor, Mohammad Azam; Kalyankar, G. D.; Talwar, G.P.

doi:10.1016/0006-3002(63)90501-8

Cited by 33 publications

(16 citation statements)

References 13 publications

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“…The particulate fractions from medulla and cortex did not inhibit the 15 OOOg supernatant of rat liver. In confirmation of the results with human and monkey cerebellum (Levine, Hall & Harris, 1963;Mansoor et al 1963), rat brain cerebellum does not have guanine-deaminase activity. Whole homogenates of the cerebellum may be expected to be inactive because of the presence of inhibitor associated with the particles, but the 15 000g supernatant was also inactive.…”

Section: Etectrophoretic Characterizationsupporting

confidence: 66%

“…The particle-associated enzyme thus had more or less the same apparent substrate affinity as soluble enzyme B, but enzyme A had a distinctly lower K.. differed both in pH-activity relationship and substrate affinity from the preparation of Mansoor, Kalyankar & Talwar (1963). The manner of preparing the initial extract was different in the two cases.…”

Section: Properties Of Guanine-deaminase Inhibitormentioning

confidence: 93%

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Studies on guanine deaminase and its inhibitors in rat tissue

Kumar

Josan

Sanger

et al. 1967

Biochemical Journal

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1. In kidney, but not in rat whole brain and liver, guanine-deaminase activity was localized almost exclusively in the 15 OOOg supernatant fraction of iso-osmotic sucrose homogenates. However, as in brain and liver, the enzymic activity recovered in the supernatant was higher than that in the whole homogenate. The particulate fractions of kidney, especially the heavy mitochondria, brought about powerful inhibition of the supernatant guanine-deaminase activity. 2. In spleen, as in kidney, guanine-deaminase activity was localized in the 15 OOOg supernatant fraction of iso-osmotic sucrose homogenates. However, the particulate fractions did not inhibit the activity of the supernatant. 3. Guanine-deaminase activity in rat brain was absent from the cerebellum and present only in the cerebral hemispheres. The inhibitor of guanine deaminase was located exclusively in the cerebellum, where it was associated with the particles sedimenting at 5000g from sucrose homogenates. 4. Homogenates of cerebral hemispheres, the separated cortex or the remaining portion ofthe hemispheres had significantly higher guaninedeaminase activity than homogenates of whole brain. The enzymic activity of the suboellular particulate fractions was nearly the same. 5. Guanine deaminase was purified from the 15 OOOg supernatant of sucrose homogenates of whole brain. The enzyme separated as two distinct fractions, A and B, on DEAE-cellulose columns. 6. The guanine-deaminase activity of the light-mitochondrial fraction of whole brain was fully exposed and solubilized by treatment with Triton X-100, and partially purified. 7. Tested in the form of crude preparations, the inhibitor from kidney did not act on the brain and liver supernatant enzymes and the inhibitor from cerebellum did not act on kidney enzyme, but the inhibitor from liver acted on both brain and kidney enzyme. 8. The inhibitor of guanine deaminase was purified from the heavy mitochondria of whole brain and liver and the 5000g residue of cerebellum, isolated from iso-osmotic homogenates. The inhibitor appeared to be protein in nature and was heat-labile. The inhibition of the enzyme was non-competitive. 9. Kinetic, immunochemical and electrophoretic studies with the preparations purified from brain revealed that the enzyme from light mitochondria was distinct from enzyme B from the supernatant. A distinction between the two forms of supernatant enzyme was less certain. 10. Guanine deaminase isolated fromlight mitochondria ofbrain did not react with 8-azaguanine or with the inhibitor isolated from heavy mitochondria.

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Section: Etectrophoretic Characterizationsupporting

confidence: 66%

Section: Properties Of Guanine-deaminase Inhibitormentioning

confidence: 93%

Studies on guanine deaminase and its inhibitors in rat tissue

Kumar

Josan

Sanger

et al. 1967

Biochemical Journal

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“…However, guanine deaminase from tea leaves seemed to have double peaks of optimum activity, at pH 7.0-7.5 and pH 8.5, as was the case for guanine deaminase from the rat brain. 4 ) After keeping the enzymes at various pHs (4 to 11) for 1 h at 30 o e, the remaining activities were assayed. Guanosine deaminase was stable at pH 6 to 9, and guanine deaminase, at pH 4 to 9.…”

mentioning

confidence: 99%

Guanosine Deaminase and Guanine Deaminase from Tea Leaves

Negishi

Ozawa

Imagawa

1994

Bioscience, Biotechnology, and Biochemistry

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“…According to the tissue distribution of guanase in man (8,10), which is very similar to that in rats and monkeys (13), diseases of liver, er, a further 5 patients with already normalized liver function tests showed a normalization of serum guanase levels within 2 months. These results favor the assumption that guanase, being ultimately normalized, might be a sensitive indicator for the restoration of liver damage following acute viral hepatitis.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Serum Guanase in Hepatic Diseases

Kuzmits¹,

Seyfried²,

Wolf³

et al. 1980

Enzyme

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Serum guanase activity was measured in 20 healthy adults and in 62 patients with acute viral hepatitis, chronic active hepatitis, chronic persistent hepatitis, liver cirrhosis and fatty liver. Guanase and γ-GT in patients were elevated in 87 and 64%, respectively. Elevated guanase activities were found in most cases of acute viral hepatitis, as well as in chronic hepatopathies. In patients with acute viral hepatitis pathologic activities of guanase were found following partial or total normalization of other liver function tests.

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Brain guanine deaminase: Purification, properties and regional distribution

Cited by 33 publications

References 13 publications

Studies on guanine deaminase and its inhibitors in rat tissue

Studies on guanine deaminase and its inhibitors in rat tissue

Guanosine Deaminase and Guanine Deaminase from Tea Leaves

Evaluation of Serum Guanase in Hepatic Diseases

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