Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 arrow Request Permissions
Google Scholar
Right arrow Articles by SHIMADA, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by SHIMADA, T.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Biochem, 1970, Vol. 67, No. 2 185-198
© 1970 Japanese Biochemical Society

research-article

The Active Site of Myosin A-Adenosine Triphosphatase*

VIII. Modification of the Enzyme with Diazonium-1H-Tetrazole

TAKAMICHI SHIMADA

Department of Biology, Faculty of Science, Osaka University Toyonaka, Osaka

  1. Myosin was treated with DHT (diazonium-1H-tetrazole) in the presence or absence of Mg-ATP. Results indicated that the SH-groups of myosin were modified by DHT.
  2. To prevent reaction of the SH-groups of myosin with DHT, the groups were blocked reversibly by DGM through their conversion to disulfide bonds. The Ca2+.ATPase [EC 3.6.1.3 [EC] [EC] ] activity of myosin disappeared on treatment with DGM (dithiodiglycolic acid dimethyl ester) for 50 hr and the amount of free SH-groups decreased to 2 moles per mole of myosin. The Ca2+ATPase activity was restored to the original level by reversing the blocking reaction with excess ßME or DTT.
  3. DGM-treated myosin was treated with DHT, and then with ß-ME or DTT. The Ca2+-ATPase activity decreased linearly with increase in the amount of monoazotyrosine in myosin, and complete inactivation occurred when approximately one mole of monoazo-tyrosine was formed per 4.0x105g of myosin. During treatment of DGM-treated myosin with DHT, the Ca2+-ATPase activity was protected to some extent by the presence of Mg-ATP.
  4. H-Meromyosin prepared by tryptic digestion of azo-myosin had the same monoazo-tyrosine content as the parent myosin. All the monoazo-tyrosine was present in the f-subunit.
  5. When a few moles of tyrosine residues per mole of myosin were modified with DHT, myosin became soluble even in water. One mole of tyrosine residue per mole of L-meromyosin fraction 1 reacted specifieally with DHT, and filament formation in L-meromyosin fraction 1 was inhibited by this modification with DHT.

*This investigation was supported by United States Public Health Service Research Grant AM-08303, and by grants from the Muscular Dystrophy Associations of America, Inc., Toyo Rayon Science Foundation, and the Ministry of Education of Japan.


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


This article has been cited by other articles:


Home page
 Cold Spring Harb Symp Quant BiolHome page
Y. Tonomura, Y. Hayashi, and A. Inoue
Formation and Decomposition of the Myosin-Phosphate-ADP Complex in the Myosin-ATPase Reaction
Cold Spring Harb Symp Quant Biol, January 1, 1973; 37(0): 169 - 178.
[Abstract] [PDF]


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.