File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Conference Paper: A possible mechanism for the control of adenosine formation by changes in pH in rat skeletal muscle

TitleA possible mechanism for the control of adenosine formation by changes in pH in rat skeletal muscle
Authors
Issue Date1998
PublisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/34597
Citation
Drug Development Research, 1998, v. 43 n. 1, p. 22, abstract no. 85 How to Cite?
AbstractUnder in-vivo conditions, adenosine output from oxidative skeletal muscle is stimulated by a decrease in pH. The present experiments were undertaken to investigate the enzymatic control of adenosine formation by changes in pH. The membrane and cytosolic fractions of rat oxidative muscle tissues (soleus) were separated by differential centrifugation. The V,, and K, of the adenosineforming enzyme 5’-nucleotidase (ND) were determined at pH values of 6.5, 7.0, 7.5 and 9.0; the rate of adenosine formation was estimated from these data and literature value for the substrate concentration. For the membrane bound (ecto-) ND, the highest V max was found at pH 7.5, which was 1.7, 1.2 and 1.9 times that at pH 6.5, 7.0 and 9.0, respectively, whereas the affinity (reciprocal of K,) of ecto-ND for AMP was decreased as the pH was increased from 6.5 to 9.0. Therefore, the estimated rates of adenosine formation (nmol/min/g wet. wt.) by ecto-ND were 50.4 at pH 6.5, 48.5 at pH 7.0, 37.0 at pH 7.5 and 19.7 at pH 9.0, respectively. For the soluble (cytosolic) ND, the V,, was increased as the pH was increased from 6.5 to 9.0, but the affinity of cytosolic ND for AMP was similar under all conditions. The estimated rate of adenosine formation by cytosolic ND did not exceed 0.7 nmol/min/g wet. wt. at any pH. These results suggest that in oxidative skeletal muscle (1) the increased adenosine formation during pH depression is the result of the increased affinity (decreased K, value) of the ecto-ND for the substrate (AMP) and (2) the rate of adenosine formation by the membrane bound ecto-ND is sufficient to account for the adenosine release observed under in-vivo conditions such as muscle contractions. On the other hand, the V,, and K, of the cytosolic ND indicate that it is unlikely to account for adenosine formation in skeletal muscle in-vivo.
DescriptionSession - Purines: Release and Metabolism
Persistent Identifierhttp://hdl.handle.net/10722/104970
ISSN
2015 Impact Factor: 0.984

 

DC FieldValueLanguage
dc.contributor.authorCheng, B-
dc.contributor.authorBallard, HJ-
dc.date.accessioned2010-09-25T22:14:57Z-
dc.date.available2010-09-25T22:14:57Z-
dc.date.issued1998-
dc.identifier.citationDrug Development Research, 1998, v. 43 n. 1, p. 22, abstract no. 85-
dc.identifier.issn0272-4391-
dc.identifier.urihttp://hdl.handle.net/10722/104970-
dc.descriptionSession - Purines: Release and Metabolism-
dc.description.abstractUnder in-vivo conditions, adenosine output from oxidative skeletal muscle is stimulated by a decrease in pH. The present experiments were undertaken to investigate the enzymatic control of adenosine formation by changes in pH. The membrane and cytosolic fractions of rat oxidative muscle tissues (soleus) were separated by differential centrifugation. The V,, and K, of the adenosineforming enzyme 5’-nucleotidase (ND) were determined at pH values of 6.5, 7.0, 7.5 and 9.0; the rate of adenosine formation was estimated from these data and literature value for the substrate concentration. For the membrane bound (ecto-) ND, the highest V max was found at pH 7.5, which was 1.7, 1.2 and 1.9 times that at pH 6.5, 7.0 and 9.0, respectively, whereas the affinity (reciprocal of K,) of ecto-ND for AMP was decreased as the pH was increased from 6.5 to 9.0. Therefore, the estimated rates of adenosine formation (nmol/min/g wet. wt.) by ecto-ND were 50.4 at pH 6.5, 48.5 at pH 7.0, 37.0 at pH 7.5 and 19.7 at pH 9.0, respectively. For the soluble (cytosolic) ND, the V,, was increased as the pH was increased from 6.5 to 9.0, but the affinity of cytosolic ND for AMP was similar under all conditions. The estimated rate of adenosine formation by cytosolic ND did not exceed 0.7 nmol/min/g wet. wt. at any pH. These results suggest that in oxidative skeletal muscle (1) the increased adenosine formation during pH depression is the result of the increased affinity (decreased K, value) of the ecto-ND for the substrate (AMP) and (2) the rate of adenosine formation by the membrane bound ecto-ND is sufficient to account for the adenosine release observed under in-vivo conditions such as muscle contractions. On the other hand, the V,, and K, of the cytosolic ND indicate that it is unlikely to account for adenosine formation in skeletal muscle in-vivo.-
dc.languageeng-
dc.publisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/34597-
dc.relation.ispartofDrug Development Research-
dc.rightsDrug Development Research. Copyright © John Wiley & Sons, Inc.-
dc.rightsPreprint: This is the pre-peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Postprint: This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Special Statement for Preprint only Before publication: 'This is a preprint of an article accepted for publication in [The Journal of Pathology] Copyright © ([year]) ([Pathological Society of Great Britain and Ireland])'. After publication: the preprint notice should be amended to follows: 'This is a preprint of an article published in [include the complete citation information for the final version of the Contribution as published in the print edition of the Journal]' For Cochrane Library/ Cochrane Database of Systematic Reviews, add statement & acknowledgement : ‘This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 20XX, Issue X. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.’ Please include reference to the Review and hyperlink to the original version using the following format e.g. Authors. Title of Review. Cochrane Database of Systematic Reviews 20XX, Issue #. Art. No.: CD00XXXX. DOI: 10.1002/14651858.CD00XXXX (insert persistent link to the article by using the URL: http://dx.doi.org/10.1002/14651858.CD00XXXX) (This statement should refer to the most recent issue of the Cochrane Database of Systematic Reviews in which the Review published.)-
dc.titleA possible mechanism for the control of adenosine formation by changes in pH in rat skeletal muscle-
dc.typeConference_Paper-
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0272-4391&volume=43&spage=22&epage=&date=1998&atitle=A+possible+mechanism+for+the+control+of+adenosine+formation+by+changes+in+pH+in+rat+skeletal+muscleen_HK
dc.identifier.emailBallard, HJ: ballard@hkucc.hku.hk-
dc.identifier.authorityBallard, HJ=rp00367-
dc.identifier.doi10.1002/(SICI)1098-2299(199801)43:1<16::AID-DDR2>3.0.CO;2-T-
dc.identifier.hkuros37033-
dc.identifier.volume43-
dc.identifier.issue1-
dc.identifier.spage22, abstract no. 85-
dc.identifier.epage22, abstract no. 85-
dc.publisher.placeUnited States-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats