fulltext.study @t Gmail

Pharmacokinetics, immunogenicity and anticancer efficiency of Aspergillus flavipesl-methioninase

Paper ID Volume ID Publish Year Pages File Format Full-Text
17104 42641 2012 11 PDF Available
Title
Pharmacokinetics, immunogenicity and anticancer efficiency of Aspergillus flavipesl-methioninase
Abstract

Methionine starvation can powerfully modulate DNA methylation, cell cycle transition, polyamines and antioxidant synthesis of tumor cells, in contrary to normal ones. Aspergillus flavipesl-methioninase was previously characterized by our studies, displaying affordable biochemical properties comparing to Pseudomonas putida enzyme (ONCASE). Thus, the objective of current study was to evaluate the catalytic properties of Af-METase in New Zealand rabbits, exploring its antitumor efficacy. In vivo, Af-METase (40.8 U/ml) have T1/2 19.8 h, elimination constant 0.088 U/h and apparent volume distribution 85 U/ml. Also, Af-METase has two maxima one at A280 nm (apo-enzyme) and at A420 nm (internal Schiff base of PLP), unlike control plasma (without enzyme). The two peaks of absorption spectra were detected maximally at 15 min then the absorbance at 420 nm was subsequently decreased with circulation time, due to dissociation of the co-enzyme. The A280/420 ratio was increased from 1.69 to 5.81 with circulation time from 15 to 30 h. Rabbits plasma methionine was depleted from 18.7 μM (control) to 8.8 μM after 1 h of enzyme injection and completely omitted after 2 h till 19 h, assuming the sustainability of negligible levels of methionine (<2 μM) in plasma of rabbits, for about 17 h. Upon infusion of PLP, the T1/2 of Af-METase was significantly prolonged by 3.2 fold, assuming the fully reconstitution of the enzyme. The holo-AfMETase still retained its co-enzyme, completely, till 33 h of PLP infusion. From spectral studies, the internal aldimine linkage of apo-Af-METase was constructed upon PLP infusion, with fully catalytic structure after less than 4 h of its infusion, the A280/420 ratio being not relatively changed till 45 h. After 25 days of last enzyme dose, the titer of IgG was increase by about 1.66 fold comparing to control (without enzyme). However, IgM was not detected along the tested challenge points. In vitro, plasma anti-Af-METase neutralizing antibodies (NAb) were assessed, with no significant reduction on activity of Af-METase by Nab. All the hematological parameters were in normal range, otherwise, the RBCs titer and platelet level was slightly increased, after 25 days of Af-METase injection, comparing to control. There is no obvious negative effect on chemistry of liver, kidney, glucose, lipids, and other electrolytes. Additionally, the anticancer activity of Af-METase was evaluated against five types of human cancer cell lines, in vitro. The enzyme showed a powerful activity against prostate (PC3), liver (HEPG2) and breast (MCF7) cancers, with IC50 0.001 U/ml, 0.26 U/ml and 0.37 U/ml, respectively.

► l-Methioninase with promising pharmacokinetic properties in vivo. ► l-Methioninase with longer half-life time in vivo, low antigenic properties. ► l-Methioninase with powerful activity against various cell lines in vitro.

Keywords
Aspergillus flavipes; l-Methioninase; Pharmacokinetics; Antigenicity; Anticancer activity
First Page Preview
Pharmacokinetics, immunogenicity and anticancer efficiency of Aspergillus flavipesl-methioninase
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 51, Issue 4, 10 September 2012, Pages 200–210
Authors
, , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us