ABSTRACT
We partially purified 1-aminocyclopropane-1-carboxylate (ACC) oxidase from senescing petals of carnation (Dianthus caryophyllus L. cv. Nora) flowers and investigated its general characteristics, and, in particular, the inhibition of its activity by ACC analogs. The enzyme had an optimum pH at 7-7.5 and required Fe2+, ascorbate and NaHCO3 for its maximal activity. The Km for ACC was calculated as 111-125 microM in the presence of NaHCO3. Its M(r) was estimated to be 35 and 36 kDa by gel-filtration chromatography on HPLC and SDS-PAGE, respectively, indicating that the enzyme exists in a monomeric form. These properties were in agreement with those reported previously with ACC oxidases from different plant tissues including senescing carnation petals. Among six ACC analogs tested, 1-aminocyclobutane-1-carboxylate (ACBC) inhibited most severely the activity of ACC oxidase from carnation petals. ACBC acted as a competitive inhibitor with the Ki of 20-30 microM. The comparison between the Km for ACC and the Ki for ACBC indicated that ACBC had an affinity which was ca. 5-fold higher than that of ACC. Whereas ACC inactivated carnation ACC oxidase in a time-dependent manner during incubation, ACBC did not cause the inactivation of the enzyme. Preliminary experiments showed that ACBC and its N-substituted derivatives delayed the onset of senescence in cut carnation flowers.
Subject(s)
Amino Acid Oxidoreductases/antagonists & inhibitors , Amino Acids, Cyclic , Amino Acids/pharmacology , Plants/enzymology , Amino Acid Oxidoreductases/isolation & purification , Blotting, Western , Chromatography, Gel , Chromatography, Ion Exchange , Electrophoresis, Polyacrylamide Gel , Kinetics , Plant Physiological Phenomena , Time FactorsABSTRACT
There are 5 reported cases of meningioma complicated by chronic subdural hematoma so far as we reviewed. Considering frequency of occurrence, association of meningioma and chronic subdural hematoma is very rare. Recently, we experienced with a case of convexity menigioma complicated by chronic subdural hematoma. The patient was a 61-year-old woman who complained of headache and numbness of the left hand. She received hysteromyomectomy 28 years before but had no past history of trauma of the head. She suffered from frequent profound pain in both orbits for one year, and she consulted a neighboring practitioner due to occurrence of numbness of the left hand and malaise. Then, CT scan revealed abnormalities, so that she was referred to our center. On admission, neurological oxamination revealed no abnormalities but plain X-ray film of the skull showed a round destruction in the right parieral bone. CT scan showed a round high density area of 3 cm in diameter in the right parietal region, this is markedly enhanced with contrast media. There is a crescent-shaped low density area extending forward from the high density area. The body of the right lateral ventricle is totally collapsed. Selective arteriography of the right external carotid revealed tumor stain in the parietal region. Therefore, under the diagnosis of association of chronic subdural hematoma and convexity meningioma, craniotomy of the right frontal, parietal and temporal regions was carried out and a meningioma of 10 g, and a subdural hematoma with its capsule touching the maningioma were entirely extirpated.(ABSTRACT TRUNCATED AT 250 WORDS)
