Skip Navigation

Cardiovascular Research 1992 26(2):143-147; doi:10.1093/cvr/26.2.143
© 1992 by European Society of Cardiology
This Article
Right arrow Full Text (PDF)
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Borst, M. M
Right arrow Articles by Schrader, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Borst, M. M
Right arrow Articles by Schrader, J.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Copyright © 1992, European Society of Cardiology

S-Adenosylhomocysteine hydrolase activity in human myocardium

Mathias M Borst, Andreas Deussen and Jürgen Schrader

Department of Physiology, Heinrich-Heine University, Dusseldorf, Germany: M M Borst, A Deussen, J Schrader.

Correspondence to Dr Borst, at Medizinische Klinik 111, Universitat Heidelberg, Bergheimer Str 58, D-W-6900 Heidelberg, Germany

Objective: Measurement of S-adenosylhomocysteine (SAH) accumulation in the heart reflects the concentration of free cytosolic adenosine and is thus a sensitive indicator of regional myocardial ischaemia. To evaluate the possibility of applying this method in combination with "C-SAH positron emission tomography (PET) to patients with ischaemic heart disease the activity of SAH hydrolase in human heart muscle and its regional distribution were studied. Methods: Myocardium from patients with dilated cardiomyopathy (n=4), hypertrophic obstructive cardiomyopathy (HOCM, n=6), and mitral stenosis (n=3) was analysed. Additional studies were performed in myocardium, isolated cardiomyocytes, and endothelial cells from dog and guinea pig hearts. Enzyme activity in synthetic and hydrolytic direction including kinetic data (Vmax, KM values, pH dependency) was measured in the cytosolic fraction of myocardial tissue and cell extracts, using high performance liquid chromatography and photometric methods, respectively. Results: Rates of SAH synthesis (Vmaxx) in the left ventricle in dilated cardiomyopathy, mitral stenosis, and HOCM were 0.8 (SEM 0.1), 1.0 (0.2), and 1.7 (0.1) nmol·min–1·mg–1 protein respectively. KM values for DL-homocysteine, adenosine, and SAH in HOCM were 187, 2.2, and 3.4 µM, respectively. Enzyme activity was homogeneously distributed among right and left atria, right and left ventricles, and septum. Additional studies in homogenated muscle and isolated cardiomyocytes of guinea pig and canine hearts showed activities similar to man. Conclusions: (1) SAH hydrolase activity in the human heart is quantitatively comparable to that found in other mammals but certain myocardial diseases may go along with changes in SAH hydrolase activity; (2) the kinetic properties, absolute amounts, and homogeneous distribution of the enzyme may permit the non-invasive determination of free adenosine in the human heart by PET.

KEYWORDS adenosine; dilated cardiomyopathy; endothelium; enzyme kinetics; homocysteine; hypertrophic obstructive; cardiomyopathy; positron emission tomography; SAH hydrolase

Surgical specimens from patients with mitral valve disease and with hypertrophic obstructive cardiomyopathy were kindly provided by Professor H D Schulte, Diisseldorf, and specimens from explanted hearts by Professor H G Borst, Hannover, Germany.

Dr Borst was supported by Deutsche Forschungsgemeinschaft, grant BO 813/1-1.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.