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M Okada

Publications and source records attributed to M Okada.

At least 1,765 records · Page 98Linked to original sources
PubMed1979

Affinity chromatography of putrescine oxidase from Micrococcus rubens and spermidine dehydrogenase from Serratia marcescens.

Putrescine oxidase [EC 1.4.3.4], putrescine : oxygen oxidoreductase (deaminating) (flavin-containing), from Micrococcus rubens and spermidine dehydrogenase from Serratia marcescens were adsorbed on amine-Sepharose 4B in which one of the terminal amino groups of diamine or triamine was covalently bound to Sepharose 4B leaving the other terminal amino group(s) free. The affinities of these enzymes for the amine-Sepharose 4B increased on increasing the chain length of the methylene groups in the immobilized amines and fell upon addition of the substrate. The affinity of putrescine oxidase modified with 1-ethyl-3-(3-dimethylamino-propyl)-carbodiimide (EDC) was reduced in comparison with that of the native enzyme so far as 1,12-diaminododecane-Sepharose 4B was concerned. From these results, it can be concluded that the interactions between the enzyme and the amine-Sepharose result from specific affinities mediated through the active sites of the enzymes. It is suggested that spermidine dehydrogenase as well as putrescine oxidase has as anionic point and a hydrophobic region in the active site. On the basis of these results, the applicability of the enzyme affinities to purification procedures was examined. When partially purified enzymes were subjected to affinity chromatography, the following results were obtained. Putrescine oxidase gave a purification factor of 40-fold with about 100% recovery on a 1,12-diaminododecane-Sepharose column. In the case of spermidine dehydrogenase, the purification factor and recovery on a 1,8-diaminooctane-Sepharose column were about 1,200-fold and 86%, respectively. By introducing affinity chromatography as a purification step, each enzyme could be purified more simply and with higher recovery.

Chromatography, Affinity↗
PubMed1979

Substrate binding characteristics of the active site of spermidine dehydrogenase from Serratia marcescens.

The substrate specificity of spermidine dehydrogenase from Serratia marcescens was studied using many kinds of naturally occurring and synthetic polyamines. Diamines inhibited the enzyme competitively and their inhibitor constants tended to decrease with increasing methylene chain length in the diamines. All of the triamines and tetramines examined were active as substrates, and the amines containing a 4-aminobutylimino moiety (NH2(CH2)4NH-) in their structures were more active. N-Alkylputrescine was also oxidized by the enzyme. All of the amines containing a 4-aminobutylimino group were oxidized to form 1-pyrroline stoichiometrically as one of the products. Tetramines containing a 3-aminopropylimino group (NH2(CH2)3NH-) were oxidized to form 1,3-diaminopropane. However, in the case of an amine containing both 4-aminobutylimino and 3-aminopropylimino groups, the imino moiety of the former was preferentially oxidized by the enzyme. On the basis of the substrate specificity, the binding characteristics of the enzyme are discussed and a subsite model for the binding site is proposed.

Amines↗
PubMed1979

[Large abdominal pseudocyst as a complication of ventriculoperitoneal shunt--diagnosis by ultrasonography and whole body CT scan (author's transl)].

We report a case in which a large abdominal pseudocyst developed following a ventriculo-peritoneal shunt (V-P shunt) for hydrocephalus due to pineal germinoma. A 24-year-old man had undergone a V-P shunt and radiotheraphy for unbiopsied posterior third ventricle tumor. Four years after operation he was readmitted because of double vision, conjugate upward gaze palsy and a large abdominal mass. Preoperative diagnosis of abdominal pseudocyst was made by abdominal computed tomography and ultrasonotomography. The shunt tube was clearly deomonstrated in the cavity by computed tomography. It is suggested that, in a patient suspicious of having abdominal pseudocyst who developed abdominal symptoms and signs following V-P shunt, abdominal computed tomography and/or ultrasonotomography provide a definitive diagnosis of this entity.

Abdomen↗
PubMed1979

Substrate specificity and reaction mechanism of putrescine oxidase.

Putrescine oxidase [EC 1.4.3.4] of Micrococcus rubens oxidizes many kinds of synthetic polyamines: triamines (spermidine types), tetramines (spermine types), and N-substituted putrescines. Polyamines possessing terminal 4-aminobutylimino groups in their structures were more active as substrates. Putreanine was oxidized at a rate comparable to that of putrescine, and was converted to 1-pyrroline and beta=alanine. Activities and Km values for polyamines were affected by the substituent attached to the 4-aminobutylimino group of the polyamine, and especially by its methylene chain length. It was also found that two types of oxidation occurred in the oxidation of polyamines by putrescine oxidase. When the moieties attached to the 4-aminobutylimino groups in polyamines were less hydrophobic, these polyamines were oxidized at the secondary amino groups to form 1-pyrroline. Polyamines which contained a hydrophobic substituent attached to the 4-aminobutylimino moiety to form ammonia. N,N'-Bis (4-aminobutyl)-1,3-diaminopropane ([II, 4-3-4]) and N-(4-aminobutyl)-N'-(3-aminopropyl)-1,3-diaminopropane ([II, 4-3-3]) were oxidized to form 1-pyrrolinium salt derivatives as a result of oxidation of the terminal primary amino groups. It was concluded that the essential structure for substrates of putrescine oxidase is a 4-aminobutylimino group (NH2(CH2)4NH-).

Kinetics↗
PubMed1978

Concanavalin A agglutination of bladder cells of rats treated with bladder carcinogens; a rapid new test to detect bladder carcinogens.

N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), which is a potent, specific bladder carcinogen in rats, and its related compounds were orally administered to rats for 1 week. The bladder cells were isolated by the treatment with EDTA and sonication and they were subjected to agglutination assay by concanavalin A (Con A). Bladder cells obtained from rats treated with BBN, N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN), N-ethyl-N-(4-hydroxybutyl)nitrosamine (EHBN) and N-butyl-N-(2-hydroxyethyl)nitrosamine (BHEN) were agglutination-positive, while those cells treated with N-tert-butyl-N-(4-hydroxybutyl)-nitrosamine (t-BBH) and N-butyl-N-(3-hydroxypropyl)nitrosamine (BHPN) were negative. Results obtained by this method were highly correlated with the known carcinogenicity of BBN and its analogues. Therefore, this method could be used for rapid screening of bladder carcinogens.

Animals↗
PubMed1978

Subunit topography of RNA polymerase (E. coli) in the complex with DNA.

E. Coli RNA polymerase binding to different DNAs (from E. Coli, 5-bromodeoxyuridine (BrdUrd) substituted DNA and poly [d(BrU-A)] was induced with ultraviolet (U.V.) light to form protein-DNA crosslinked complexes. Two independent methods of analysis, polyacrylamide gel electrophoresis in SDS and chloroform extraction indicated the formation of a stable complex between the enzyme and DNA. The complexes were formed under different ionic strength conditions, at low enzyme to DNA ratios in order to approach the conditions of specific binding. In contrast there was no crosslinking of the complex in 1 M KCl solution which dissociates the enzyme from DNA. The efficiency of formation of strongly bound complex was found to be much higher with holoenzyme than with core enzyme. The following results were obtained : 1) The large subunits beta and beta' were found to be bound to DNA. 2) Relatively small amount of sigma subunit were bound to DNA while alpha subunits were essentially not attached to DNA. The high binding affinity of beta and beta' subunits was also observed in the studies of isolated subunits. These results lead to a model of enzyme-DNA complex in which the large beta and beta' subunits provide the contacts between the RNA polymerase and the DNA.

Bromodeoxyuridine↗