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Biomedical subjects

S Sakakibara

Publications and source records attributed to S Sakakibara.

At least 19 recordsLinked to original sources
PubMed1979

Changes of X-prolyl dipeptidyl-aminopeptidase activity in developing rat brain.

We found X-prolyl dipeptidyl-aminopeptidase activity in rat brain and examined the developmental changes at various ages. The total enzyme activity per brain increased until 4 weeks of age, and then decreased during maturation. Specific activity in young rat brain was higher than that in adult rat brain. The properties of the brain enzyme were different from those of pituitary and other tissues.

Aging↗
PubMed1979

Urinary polyamine levels in patients with psoriasis.

Polyamine contents in 24 h urine of 16 psoriatic patients and seven healthy individuals are measured. The average values of putrescine and spermine showed slight increase in the psoriatic group, while those of spermidine were unchanged. When psoriatic patients are divided into three groups according to the extent of their skin lesion, the putrescine level is found to be higher in the group more severely affected.

Adult↗
PubMed1979

Conformational studies of oxytocin analogues with different ring sizes. I. Circular dichroism.

Circular dichroic spectra were measured for three analogues of deamino-oxytocin of different ring sizes where the disulfide group of oxytocin is replaced by the (CH2)n group. Their backbone rings are composed of different numbers of atoms, i.e., they are nineteen, twenty and twenty-one for [1,6-aminopimelic acid]oxytocin (n = 1), [1,6-aminosuberic acid]oxytocin (n = 2) and [1,6-aminoazelaic acid]oxytocin (n = 3), respectively. The pH dependence of the circular dichroism spectra indicates that the conformation of [1,6-aminoazelaic acid]oxytocin is different from those of others and the temperature dependency reveals that the conformation of [1,6-aminopimelic acid]oxytocin is most rigid. [1,6-Aminosuberic acid]oxytocin is biologically most active among three derivatives and their biological activities are related to the conformation and internal motions of the peptide hormone analogues.

Circular Dichroism↗
PubMed1979

Reduction of serum X-prolyl dipeptidyl-aminopeptidase activity in tumour-bearing mice and reversal of reduced enzyme activity by lentinan, an anti-tumour polysaccharide.

Serum X-prolyl dipeptidyl-aminopeptidase activity which had been shown to be depressed in cancer patients was clearly reduced in mice with Ehrlich carcinoma and Sarcoma 180, and slightly reduced in mice with methylcholanthrene-induced sarcomas. The reduced enzyme activity was completely reversed during tumour regression of sarcoma 180 by administration of lentinan, which causes regression of sarcoma 180.

Animals↗
PubMed1979

A new assay of X-prolyl dipeptidyl-aminopeptidase activity in human serum with glycylproline p-phenylazoanilide as substrate.

A new assay procedure for X-prolyl dipeptidyl-aminopeptidase activity in human serum was developed with glycylproline p-phenylazoanilide tosylate as substrate. p-Phenylazoaniline liberated by the enzyme reaction was measured photometrically at 493 nm after stopping the reaction with acid. This assay was simple and sensitive, and less than 50 microliter of human serum was required for the assay. Km value was 2.5 mM and the optimum pH was 8.7. After disc gel electrophoresis of human serum, the enzyme activity could be distinctly observed as a reddish band on the gel when the gel was incubated with this substrate.

Dipeptides↗
PubMed1979

Comparison of X-prolyl dipeptidyl-aminopeptidase activity in human cerebrospinal fluid with that in serum.

X-Prolyl dipeptidyl-aminopeptidase activities in cerebrospinal fluid and serum from the same patients without neurological diseases, undergoing surgery under lumbar anesthesia, were assayed fluorometrically with a newly synthesized fluorogenic substrate, 7-glycylproline-4-methylcoumarinamide; the values were 129.1 +/- 19.5 nmoles/min/l and 54.17 +/- 3.11 mumoles/min/l (mean +/- SEM, n = 23), respectively, and there was no correlation between both activities (r = 0.0894).

Dipeptides↗
PubMed1979

Correlation between X-prolyl dipeptidyl-aminopeptidase and serum amine oxidase in serum of patients with post-burn keloids.

Activities of X-prolyl dipeptidyl-aminopeptidase (EC 3.4.14.1) and amine oxidase (EC 1.4.3.6) in serum were assayed in two groups of patients, children two to nine years old and adults 23 to 60 years old, with hypertrophic scars after severe burn. The peptidase activity tended to be low initially for several months after the burn, but then returned to normal after six months. These changes were marked in the child group, less so in the adult group. Similar but less-pronounced changes were also observed in serum amino oxidase activity. The two serum enzyme activities showed a significant positive correlation (r = 0.668, p less than 0.001, n = 27) in the patients.

Adolescent↗
PubMed1978

Serum glycylproline p-nitroanilidase activity in rheumatoid arthritis and systemic lupus erythematosus.

Glycylproline p-nitroanilidase activity in serum of patients with advanced rheumatoid arthritis or with systemic lupus erythematosus but with normal hepatic function was found to be significantly lower than that of normal adult controls. Decrease of this enzyme's serum activity was more pronounced in systemic lupus erythematosus. A significant inverse correlation was observed between the enzyme activity and the duration of rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1978

Successive cleavage of N-terminal Arg1--Pro2 and Lys3-Pro4 from substance P but no release of Arg1-Pro2 from bradykinin, by X-Pro dipeptidyl-aminopeptidase.

X-Pro dipeptidyl-aminopeptidase (EC 3.4.14.1) purified homogeneously from the human submaxillary gland was proved to hydrolyze N-terminal dipeptide Arg1-Pro2 and subsequent dipeptide Lys3-Pro4 from substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-gly-Leu-Met-NH2). Km and V values of hydrolysis of substance P were 2.0 mM and 3.6 mumol/min per mg protein, respectively. In contrast, the N-terminal Arg-Pro of bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) was not cleaved by the enzyme.

Amino Acid Sequence↗