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M Yazawa

Publications and source records attributed to M Yazawa.

124 records · Page 7Linked to original sources
PubMed1980

Calmodulins from muscles of marine invertebrates, scallop and sea anemone.

Invertebrate calmodulins of the sea anemone and scallop muscle were isolated and their properties were compared with those of vertebrate calmodulins from rabbit muscle and pig brain. The molecular weights estimated by SDS-polyacrylamide gel electrophoresis were similar to the molecular weight (16,500) of the vertebrate calmodulins. Every calmodulin contained 1 mol each of trimethyllysine and histidine, and high contents of acidic amino acids. The marine invertebrate calmodulins contained only one tyrosine in contrast to two tyrosines in the vertebrate ones. As a result, the UV absorption spectra were clearly different. The Ca2+-induced difference UV absorption spectra of the invertebrate calmodulins were indistinguishable from those of the vertebrate ones in spite of the difference in tyrosine contents. In tryptic peptide maps of invertebrate calmodulins, a few spots different from those of vertebrate calmodulins were observed in the basic and acidic peptide regions. The calmodulins of invertebrate muscles and that of rabbit skeletal muscle were almost indistinguishable in terms of the activation profile of rabbit skeletal myosin light chain kinase.

Amino Acids↗
PubMed1978

Identification of an activator protein for myosin light chain kinase as the Ca2+-dependent modulator protein.

Myosin light chain kinase which phosphorylates g2 light chain of skeletal muscle myosin requires an activator for the activity (Yazawa, M., and Yagi, K (1977) J. Biochem. (Tokyo) 82, 287-289). This activator has now been identified as the modulator protein known to be a Ca2+-dependent regulator for phosphodiesterase, adenylate cyclase, and ATPases. The identification is based on the quantitative cross-reactivity of muscle activator protein and brain modulator protein in activating myosin light chain kinase and brain phosphodiesterase and identical properties of both proteins in regard to sensitivities to Ca2+, UV absorption spectra, UV absorption difference spectra with or without Ca2+, and mobilities upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the presence of modulator protein, the activity of myosin light chain kinase was reversibly controlled by the physiological concentration of Ca2+. We suggest that two Ca2+-receptive proteins, i.e. modulator protein and troponin-C, may play roles in the contraction-relaxation cycle of skeletal muscle.

Animals↗
PubMed1978

Modulator protein as a Ca2+-dependent activator of rabbit skeletal myosin light-chain kinase. Purification and characterization.

The Ca2+-dependent activator protein of myosin light-chain kinase, which was identified as the bovine brain modulator protein of cyclic nucleotide phosphodiesterase, was isolated from rabbit skeletal muscle. The purified protein binds about 2 Ca2+ per mol in a medium containing 5 mM MgCl2, 10 micron CaCl2, and 0.1 M KCl at pH 6.8. The Ca2+ binding caused a conformational change of the activator protein which was measured by difference ultraviolet absorption spectroscopy. In the same Ca2+ concentration range as that causing the conformational change, activation of myosin light-chain kinase was observed.

Amino Acids↗
PubMed1978

Purification of modulator-deficient myosin light-chain kinase by modulator protein-Sepharose affinity chromatography.

Modulator-deficient myosin light-chain kinase from rabbit skeletal muscle was purified by modulator protein-Sepharose 4B affinity chromatography. The purified protein showed a single band (MW 80,000) on polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and it exists as a monomer in the native state as determined by gel filtration. The modulator-deficient myosin light-chain kinase (MW 80,000), modulator protein (MW 16,500) and Ca2+ were essential for the kinase activity. The half-maximal activity of the kinase in the presence of excess modulator protein with 10 mM MgCl2 was at pCa 5.1, where full activity of actomyosin-ATPase is observed in the presence of the troponin--tropomyosin system. Assuming a rapid equilibrium between myosin light-chain kinase and two substrates, ATP and g2 light-chain, Km values for ATP and g2 light chain were evaluated as 0.28 mM and 0.024 mM, respectively. Vm/e was 5.7 s-1.

Adenosine Triphosphatases↗
PubMed1977

Calcium-binding subunit of myosin light chain kinase.

Myosin light chain kinase from frozen rabbit skeletal muscle was separated into two protein components by DEAE-cellulose column chromatography. One component (MW 20,000) was a Ca2+-binding protein. Both components and Ca2+ were essential for the enzyme activity.

Animals↗
PubMed1976

Studies on tyrosine residues in porcine muscle adenylate kinase. Circular dichroism spectra and chemical modification with tetranitromethane.

Substrate-induced conformational change of porcine muscle adenylate kinase (EC 2.7.4.3) is evidenced by a change in circular dichroism spectra in the near ultraviolet. In the absence of tryptophan in porcine muscle adenylate kinase, the spectral change may be assigned to a perturbation of tyrosine chromophore(s). The spectral change was specific for adenine nucleotide binding and was greater with ATP than with AMP. In the x-ray model, Tyr153 and Tyr154 are located at a hinge region of two domains which form a deep active site cleft and are therefore susceptible to conformational change on substrate binding. Adenylate kinase was treated with equimolar tetranitromethane. The yellow-colored product, separated from unmodified enzyme by substrate gradient elution on a phosphocellulose column, had about 1 mol of nitrotyrosine per mol of the enzyme by amino acid analysis and showed a slightly higher Km value than native enzyme for ADP (Km = 0.50 mM compared with 0.25 mM for native adenylate kinase). Spectrophotometric titration of nitroadenylate kinase gave pKa 8.4 for the dissociation constant of the nitrotyrosyl hydroxyl group. On binding ATP the pKa value increased to 9.0 while AMP binding caused very little change. By peptide mapping of the carboxypeptidase digestion product, 0.70 mol of nitro group per mol of adenylate kinase was detected on Tyr153 and a small amount of nitro group was also found on Tyr95. From these results it is proposed that Tyr153 is directly or indirectly involved in the binding of ATP.

Adenosine Diphosphate↗
PubMedDate not supplied

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome in Nagano, Japan: clinical, radiological, and cytokine studies of 13 patients.

OBJECTIVE: Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) has so far been reported almost exclusively from the USA and Europe. We carried out this study to define the clinical characteristics of this syndrome in Japanese patients. METHODS: Prospectively, we identified 13 Japanese patients with RS3PE (5 men and 8 women, age 72.7 +/- 11.8 years (mean +/- SD)) without underlying neoplasm. Their clinical features were summarized, pertinent laboratory data including serum/synovial interleukin-6 (IL-6) concentrations were obtained, and extensive radiologic studies using magnetic resonance imaging and 67gallium-citrate (67Ga) whole body scintigram were performed. RESULTS: All patients suffered from proximal arthralgia/myalgia in addition to typical distal symptoms of RS3PE, and all experienced systemic symptoms such as fever, malaise, and weight loss. In laboratory examinations, anemia and elevated inflammatory markers were often remarkable. Magnetic resonance imaging showed severe tenosynovitis of the hands. 67Ga-scintigram revealed radioisotope accumulation in both proximal and distal joints of the extremities. IL-6 activity was markedly elevated both in the serum (mean 82.4 +/- 62.1 (SD) pg/ml, normal range 0.157-2.94) and in the synovial fluid (mean 3350 +/- 633 (SD) pg/ml). CONCLUSION: Compared with cases reported previously from the USA/Europe, Japanese patients with RS3PE are characterized by more prominent systemic symptoms/signs associated with marked inflammatory responses including elevated IL-6 activity. All patients had proximal as well as distal synovitis which could be demonstrated by 67Ga-scintigram. These clinical features were very similar to those of polymyalgia rheumatica, suggesting that RS3PE and polymyalgia rheumatica are closely related disorders which may have a common pathogenesis.

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