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K Miyazaki

Publications and source records attributed to K Miyazaki.

At least 757 records · Page 42Linked to original sources
PubMed1980

Affinity chromatography of porcine pancreas deoxyribonuclease I on DNA-binding sepharose under non-digestive conditions, using its substrate-binding site.

1. DNase I from porcine pancreas, if Mg2+ was present, hydrolyzed both sDNA and dDNA, whether free or bound to Sepharose. The hydrolysis rates were maximum at pH 7.5 with the bound DNAs and at pH 7.0 with the free DNAs negligible at pH 4.0 and pH 10.5 with the free and bound DNAs. The hydrolysis was completely inhibited by 50 mM sodium citrate. 2. With 50 mM citrate buffer (Ph 4.0), DNase I was effectively adsorbed on the DNA-Sepharoses in the absence of 5 mM Mg2+. The adsorbed enzyme was effectively eluated by the buffer containing 1 M KCl (eluate). The amounts of the eluated enzyme were approximately 1.5 X 10(5) units/mg DNA with sDNA-Sepharose and approximately 3.0 X 10(5) units/mg DNA with dDNA-Sepharose. This simple adsorption-elution of the pancreas extract resulted in approximately 300-fold purification of DNase I with a yield of 95%. In the elute, the ratios in activity of trypsin, chymotrypsin and RNase to DNase I were 1/(4.0 X 10(5)), 1/(5.3 X 10(3)), and 1/(4.1 X 10(2)) as low as in the extract, respectively. In addition, the eluate was not contaminated by kallikrein or carboxypeptidases A and B. 3. Upon repeating the adsorption-elution described above, the adsorbing capacities of DNA-Sepharoses gradually deteriorated with the whole pancreas extract, but not with the precipitate of the extract formed on 60% ammonium sulfate saturation, which contained 90% of the DNase I. With the precipitate, one dDNA-Sepharose solumn was repeatedly usable at least 20-times without deterioration. The DNase I preparation thus obtained was homogeneous on SDS-polyacrylamide gel electrophoresis. 4. Conceivably, the above-mentioned adsorption of DNase I on DNA-Sepharoses was mainly due to the steric and electrostatic affinity of a relatively large moiety of the DNA molecule to the substrate-binding site, but not to the catalytic site, of the enzyme.

Animals↗
PubMed1980

Specific regulation by steroid hormones of protein kinases in the endometrium. 1. Alteration by estrogen and progesterone in levels of protein kinases in rabbit endometrium.

The alteration in activities of multiple protein kinases has been studied in the endometrium of a rabbit treated with estrogen and progesterone. The administration of estrogen or progesterone to the castrated rabbit resulted in a remarkable increase of total activity in the cytosol fraction of the endometrium. The administration of estrogen caused an increase of type I adenosine-3',5'-monophosphate-dependent (cAMP-dependent) protein kinase and a slight decrease of type II cAMP-dependent protein kinase. In contrast, the treatment with progesterone after priming administration of estrogen brought about an increase of type II cAMP-dependent protein kinase and a decrease of type I cAMP-dependent protein kinase. Therefore, the activity ratio of type II to type I decreased by estrogen and increased by progesterone. The simultaneous administration of cycloheximide abolished the stimulatory effect of respective hormones on the level of each protein kinase. The activity profile of protein kinases on DEAE-cellulose column after ovulation caused by the administration of human chorionic gonadotropin to a non-castrated rabbit was similar to that of the rabbit treated with progesterone. The results presented demonstrate the specific regulation by the steroid hormones of de novo synthesis of protein kinases in the target organ.

Animals↗
PubMed1980

Specific regulation by steroid hormones of protein kinases in the endometrium. 2. Alteration in levels of protein kinases in human endometrium during the menstrual cycle.

The alteration in the levels of multiple protein kinases has been studied in human endometrium during the menstrual cycle. Protein kinases were examined in the cytosol fraction and separated by DEAE-cellulose column chromatography. The level of type I adenosine 3',5'-monophosphate-dependent (cAMP-dependent) protein kinase was higher than that of type II cAMP-dependent protein kinase at the proliferative phase. At the late secretory phase, type I cAMP-dependent protein kinase markedly decreased, whereas type II cAMP-dependent protein kinase remained at the same level. Therefore, type II cAMP-dependent protein kinase was exclusively predominant at this phase. cAMP-dependent and cAMP-independent protein kinases with protamine increased more at the late secretory phase than at the proliferative phase. The results presented demonstrate a specific alteration in protein kinase activities during the menstrual cycle and are compatible with those obtained in rabbit endometrium (the preceding paper).

Adult↗
PubMed1980

Cyclic peptides. VIII. Synthesis and tryptic hydrolysis of cyclic depsidipeptides containing a lysine residue.

Four stereoisomers of a cyclic depsidipeptide containing a lysine and a 2-hydroxy-3-phenylpropanoic acid (Hpp) residue have been synthesized and their susceptibility toward trypsin examined. Trypsin hydrolyzed cyclo(-L-Lys-L-Hpp-) (I-LL) and cyclo(-L-Lys-D-Hpp-) (I-LD) rapidly and cyclo(-D-Lys-L-Hpp-) (I-DL) and cyclo(-D-Lys-D-Hpp-) (I-DD) very slowly. Proteolytic coefficients of these substrates and a reference compound are shown as follows: I-LL, 112; I-LD, 34; I-DL, 0.34; I-DD, 0.11, and Ac-L-Lys-OEt, 44. Possible mode of actin of trypsin on these substrates was discussed.

Amino Acid Sequence↗