Masaya Hosokawa

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Multiple carboxylesterases (EC 3.1.1.1) play an important role in the hydrolytic biotransformation of a vast number of structurally diverse drugs. These enzymes are major determinants of the pharmacokinetic behavior of most therapeutic agents containing ester or amide bonds. Carboxylesterase activity can be influenced by interactions of a variety of(More)
Five senescence-prone series of mice (P-1, P-2, P-3, P-4 and P-5) and three senescence-resistant series (R-1, R-2 and R-3) were obtained by continuous sister-brother breeding from five original litters of AKR mice with severe deterioration, and the three original litters of AKR mice with normal aging, respectively. A grading score system was adopted to(More)
Three isozymes of carboxylesterase were purified from rat liver microsomes by using Sephadex G-150 gel filtration, DE-52 ion exchange, and chromatofocusing column chromatographies. These isozymes each showed a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were immunologically different from each other as determined by(More)
Microsomal carboxylesterase activities in 12 human livers were determined using 10 kinds of carboxylesterase substrates (p-nitrophenylacetate, p-nitrophenylpropionate, p-nitrophenylbutyrate, butanilicaine, isocarboxazid, palmitoyl-coenzyme-A, malathion, clofibrate, acetanilide, and phenacetin). There were large individual differences in the 12 humans based(More)
Seven carboxylesterase isozymes were purified to electrophoretic homogeneity from liver microsomes of mouse, hamster, guinea pig, rabbit, and monkey by the same procedure used previously to obtain three isozymes from the rat, and their physical, enzymological, and immunological properties were compared with those of the rat isozymes. The substrate(More)
We measured the plasma concentrations of 7-ethyl-10-[4-(1-piperidino)-1- piperidine]carbonyloxycamptothecin (CPT-11) and the active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), after treatment with CPT-11 to rats pretreated with bis-p-nitrophenylphosphate (BNPP) which is a specific inhibitor of carboxylesterase, and non-pretreated rats. The plasma(More)
When expressed in Xenopus oocytes, GLUT1, 2 and 4 transport glucosamine with V(max) values that are three- to four-fold lower than for glucose. The K(m)s for glucosamine and glucose of GLUT1 and GLUT4 were similar. In contrast, GLUT2 had a much higher apparent affinity for glucosamine than for glucose (K(m)=0.8+/-0.1 mM vs. approximately 17-20 mM).(More)
The DNA sequence encoding a novel human brain carboxylesterase (CES) has been determined. The protein is predicted to have 567 amino acids, including conserved motifs, such as GESAGG, GXXXXEFG, and GDHGD which comprise a catalytic triad, and the endoplasmic reticulum retention motif (HXEL-COOH) observed in CES families. Their gene products exhibited(More)
We have shown that metastasis is suppressed by low-dose total-body irradiation (TBI) in tumor-bearing rats. We have evaluated the immunological effects of low-dose TBI. Total-body irradiation with 0.2 Gy was given 14 days after the implantation of 5 x 10(5) allogenic hepatoma cells (KDH-8) which produce transforming growth factor beta (TGF-beta). On day 21,(More)