pET 49b(+) DNA Novagen Novagens pET 49b(+) vector is designed for cloning and high level expression of target proteins fused with the 220 aa schistosomal glutathione S transferase Tag protein. Sigma Aldrich A visible reflection of internal imbalance. When glutathione levels are depleted and hydration drops, skin can begin to look dull, uneven, and tired. The Glow Revival Kit combines Liposomal Glutathione and GST Tag Definition & Data Protein Tagging: How to Choose a Tag for Your Protein