Rabbit Anti-Human TYR (a.a. 471-520) Polyclonal antibody

Marine byproducts have become popular research themes due to their biological significance. The black sharkskin protein hydrolysate-based antioxidant peptides were firstly investigated in this study. The black sharkskin-derived novel antioxidant peptide demonstrating 81.05% free radical scavenging activity to ABTS at 500 mu g/mL, was identified to be Ala-Thr-Val-Tyr (ATVY). The crucially antioxidant interaction site of ATVY action on ABTS was determined to be Tyr in the N-terminal. ATVY reacted with ABTS to generate polyphenol-derived adducts which subsequently degraded into a purple compound. The MS/MS showed it was formed by covalently bonding through the phenol group of ATVY to the N group of ABTS. The free radical scavenging kinetics of ATVY on ABTS demonstrated a two-phase reaction process. These findings reveal the action mechanism of ATVY on ABTS, implying ATVY can be incorporated in the production of antioxidant food additives.

Pseudomonas aeruginosais a multidrug-resistant (MDR) pathogen and a causative agent of both nosocomial and community-acquired infections. The genes (tyrS andtyrZ) encoding both forms ofP. aeruginosatyrosyl-tRNA synthetase (TyrRS-S and TyrRS-Z) were cloned and the resulting proteins purified. TyrRS-S and TyrRS-Z were kinetically evaluated and theK(m)values for interaction with Tyr, ATP, and tRNA(Tyr)were 172, 204, and 1.5 mu M and 29, 496, and 1.9 mu M, respectively. Thek(cat)(obs)values for interaction with Tyr, ATP, and tRNA(Tyr)were calculated to be 3.8, 1.0, and 0.2 s(-1)and 3.1, 3.8, and 1.9 s(-1), respectively. Using scintillation proximity assay (SPA) technology, a druglike 2000-compound library was screened to identify inhibitors of the enzymes. Four compounds (BCD37H06, BCD38C11, BCD49D09, and BCD54B04) were identified with inhibitory activity against TyrRS-S. BCD38C11 also inhibited TyrRS-Z. The IC(50)values for BCD37H06, BCD38C11, BCD49D09, and BCD54B04 against TyrRS-S were 24, 71, 65, and 50 mu M, respectively, while the IC(50)value for BCD38C11 against TyrRS-Z was 241 mu M. Minimum inhibitory concentrations (MICs) were determined against a panel of clinically important pathogens. All four compounds were observed to inhibit the growth of cultures of both Gram-positive and Gram-negative bacteria organisms with a bacteriostatic mode of action. When tested against human cell cultures, none of the compounds were toxic at concentrations up to 400 mu g/mL. In mechanism of inhibition studies, BCD38C11 and BCD49D09 selectively inhibited TyrRS activity by competing with ATP for binding. BCD37H06 and BCD54B04 inhibited TyrRS activity by a mechanism other than substrate competition.