Comparison of two agricultural wastes for phenol removal via peroxidase-catalyzed enzymatic approach

© The Authors, published by EDP Sciences, 2016. Agricultural wastes of jicama and luffa skin peels were used as the source for peroxidase extraction. The extracted crude enzymes showed similar activities, 1.34U/mL and 1.22U/mL for jicama and luffa peroxidase respectively. These peroxidases were used to treat phenol under varying operating conditions of buffer pH, hydrogen peroxide concentration, enzyme volume and temperature. Jicama peroxidase demonstrated a phenol removal efficiency of approximately 90% at buffer pH 7, 1mM hydrogen peroxide using 1.5mL enzyme at 25°C. Luffa peroxidase required a higher dosage of hydrogen peroxide, and exhibited a removal efficiency of 84% at 8mM with other operating conditions same as jicama peroxidase. Jicama peroxidase is sensitive to pH change and more susceptible to thermal denaturation. Luffa peroxidase showed a better stability in terms of temperature

Bcl11a Deficiency Leads to Hematopoietic Stem Cell Defects with an Aging-like Phenotype

SummaryB cell CLL/lymphoma 11A (BCL11A) is a transcription factor and regulator of hemoglobin switching that has emerged as a promising therapeutic target for sickle cell disease and thalassemia. In the hematopoietic system, BCL11A is required for B lymphopoiesis, yet its role in other hematopoietic cells, especially hematopoietic stem cells (HSCs) remains elusive. The extensive expression of BCL11A in hematopoiesis implicates context-dependent roles, highlighting the importance of fully characterizing its function as part of ongoing efforts for stem cell therapy and regenerative medicine. Here, we demonstrate that BCL11A is indispensable for normal HSC function. Bcl11a deficiency results in HSC defects, typically observed in the aging hematopoietic system. We find that downregulation of cyclin-dependent kinase 6 (Cdk6), and the ensuing cell-cycle delay, correlate with HSC dysfunction. Our studies define a mechanism for BCL11A in regulation of HSC function and have important implications for the design of therapeutic approaches to targeting BCL11A

Consensus mutagenesis reveals that non-helical regions influence thermal stability of horseradish peroxidase

The enzyme horseradish peroxidase has many uses in biotechnology but a stabilized derivative would have even wider applicability. To enhance thermal stability, we applied consensus mutagenesis (used successfully with other proteins) to recombinant horseradish peroxidase and generated five single-site mutants. Unexpectedly, these mutations had greater effects on steady-state kinetics than on thermal stability. Only two mutants (T102A, T110V) marginally exceeded the wild type's thermal stability (4% and 10% gain in half-life at 50 °C respectively); the others (Q106R, Q107D, I180F) were less stable than wild type. Stability of a five-fold combination mutant matched that of Q106R, the least-stable single mutant. These results were perplexing: the Class III plant peroxidases display wide differences in thermal stability, yet the consensus mutations failed to reflect these natural variations. We examined the sequence content of Class III peroxidases to determine if there are identifiable molecular reasons for the stability differences observed. Bioinformatic analysis validated our choice of sites and mutations and generated an archetypal peroxidase sequence for comparison with extant sequences. It seems that both genetic variation and differences in protein stability are confined to non-helical regions due to the presence of a highly conserved alpha-helical structural scaffold in these enzymes