Guanase activity in normal and neoplastic human tissue

Levine, Ross L.; Hall, Thomas C.; Harris, Cynthia

doi:10.1002/1097-0142(196302)16:2<269::aid-cncr2820160218>3.0.co;2-v

Cited by 31 publications

(16 citation statements)

References 7 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 enzymic activity obtained with 8-azaguanine as substrate has been assumed by some authors to be a measure of guanine deaminase (Hirschberg et al 1952;Levine et al 1963). The findings that there exists a form of guanine deaminase that is inactive towards 8-azaguanine necessitates caution in the interpretation of data with the analogue.…”

Section: Etectrophoretic Characterizationmentioning

confidence: 99%

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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: Etectrophoretic Characterizationmentioning

confidence: 99%

Studies on guanine deaminase and its inhibitors in rat tissue

Kumar

Josan

Sanger

et al. 1967

Biochemical Journal

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“…Fpr the biological activity of 8-azaguanine derivatives, see: Roblin et al (1945); Ding et al (2004); Mitchell et al (1950); Levine et al (1963); Montgomery et al (1962); Yamamoto et al (1967); Bariana (1971); Holland et al (1975). For related structures, see: Chen & Shi (2006); Ferguson et al (1998); Li et al (2004); Maldonado et al (2006); Wang et al (2006); Xiao & Shi (2007); Zeng et al (2006Zeng et al ( , 2009 Table 1 Hydrogen-bond geometry (Å , ).…”

Section: Related Literaturementioning

confidence: 99%

6-Isopropyl-5-methoxy-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one

Zeng¹,

Wang²,

Deng³

et al. 2010

Acta Cryst E

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In the title compound, C14H15N5O2, the whole molecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intramolecular C—H⋯N hydrogen-bonding interaction may stabilize the molecular conformation. The crystal packing features weak slipped π–π interactions between the pyrimidine and the phenyl rings of symmetry-related molecules [centroid–centroid distance = 3.746 (1)Å, slippage of 1.574 Å].

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“…in humans, high äctivities have been activity can be measured via uric acid (8,9) or H 2 O 2 found in liver, kidney and brain, and little or no formed in thisreaction (10,11); O 2 consumption also activity in other organs (2,3).…”

mentioning

confidence: 99%

“…Guanine -l· H 2 The absorbance of oxidized ABTS recorded at 410 nm is directly proportional to guanase activity in the sample.…”

mentioning

confidence: 99%