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1992 Fiscal Year Final Research Report Summary

Activation Mechanism of Soluble Guanylate Cyclase and Metabolism of Cyclic GMP in Platelets

Research Project

Project/Area Number 03671109
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Laboratory medicine
Research InstitutionEhime University

Principal Investigator

SAHEKI Shuichi  Ehime Univ. School of Med, Assoc.Prof., 医学部, 助教授 (80145078)

Project Period (FY) 1991 – 1992
KeywordsGuanylate Cyclase / Cyclic GMP / Microsequensing
Research Abstract

Soluble form of guanylate cyclase is a dimer of 70k and 82k subunits containing heme and is activated by NO. In this project, first, we tried to reconstruct the enzyme from the dissociated subunits to clarify the subunit function in the activation process by NO. Second, we studied kinetics of cyclic GMP levels in platelets in response to NO(SNP).
For reconstruction experiment, large amounts of the highly purified enzyme was required. We developed a new elution method of immunoaffinity column using a single hollow fiber concentrator and succeeded in obtaining enough amounts of the enzyme. The enzyme showed two bands of the subunits on SDS-PAGE, contained 0.8 mole of heme and activated 40-fold by SNP. After complete denaturation in 8M urea or 6M Gua-HCl, the enzyme solution was diluted 100-fold with 20 mM Tris-HCl (pH=7)/20 % glycerol/1 mM DTT and incubated for up to 24 hr to recover the activity. The enzyme activity, however, could not be obtained. One of the problems must relate to the extremely unstable nature of the purified enzyme in dilute conditions, although glycerol stabilized it substantially.
The dimeric guanylate cyclase similar to that in rat lung was demonstrated in human platelet and shown to be activated 200-fold by SNP. Cyclic GMP in platelet quickly rose to maximal levels in 10 sec after SNP addition and declined to the basal levels after 30 sec. IBMX, however, blocked the decline. These implied importance of degradation as well as synthesis to regulate intracellular cyclic GMP levels.
Through this project, microsequencing technique was developed for the co-operational work on cDNA cloning of guanylate cyclase and applied successfully on other several proteins.

  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] Kuno,T.: "cDNA cloning of a neural vsinin-like Ca2+-binding protein." Biochem.Biophys.Res.Commun.184. 1219-1225 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Saheki,S.: "Hemoglobin Ehime or β57-58(E1-2)Asn-Pro→0,a new β chain variant." (Hemoglobin). (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kuno,T.: "cDNA cloning of a neural vsinin-like Ca2+-binding protein." Biochem.Biophys.Res.Commun.184(3). 1219-1225 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Saheki,S.: "Hemoglobin Ehime or bata57-58 (E1-2) Asn-Pro*0, a new batachain variant." Hemoglobin.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1994-03-24  

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