ABSTRACT
BACKGROUND: Insulin controls hyperglycemia caused by diabetes, and virtually all treatments require exogenous insulin. However, the product's extensive post-translational modifications have hindered the manufacture of recombinant insulin. RESULT: Here we report a novel production method for a monomeric B22Asp desB30 insulin analog (B22D desB30 insulin). Its precursor, DPIP, is fused to an N-terminal chitin-binding domain and intein self-cleavage tag. The fusion protein is expressed and purified from E. coli and immobilized on chitin resins. DPIP is then released using an optimized pH shift and converted to mature insulin via trypsin digest. The resulting product appears monomeric, > 90% pure and devoid of any exogenous enzyme. CONCLUSION: Thus, biologically active insulin analog can be efficiently produced in bacteria and potentially applicable in the treatment of human diabetes.
Subject(s)
Insulin/analogs & derivatives , Proinsulin/genetics , Recombinant Fusion Proteins/metabolism , Escherichia coli/genetics , Escherichia coli/growth & development , Insulin/genetics , Inteins , Protein Engineering , Protein Multimerization , Protein Splicing , Recombinant Fusion Proteins/geneticsABSTRACT
This study sought to explore a new compound polyvinyl alcohol-collagen as a wound dressing. To make the polymer, Polyvinyl alcohol (PVA) and collagen type I were put together in the ratio of 3:1, at the same time, polyethlene glycol as porogen was added, and the material was dried by air to be a membrane in shape. Then the ultimate tensile load, the hole diameter, porosity, and water absorption were measured. The cell biocompatibility was tested as well. The results showed the PVA-collagen blend had the average hole 100-150 microm in diameter, and the porosity about 90%. The ultimate tensile load reached 8.10 +/- 0.28 MPa, and water absorption was up to 185.42% +/- 6.93%. 3T3 cells grew well on the PVA-collagen member. Therefore, the PVA-collagen memberane is characterized not only by its ideal biomechanical ability and biocompability, but also by its ideal hole diameter, porosity and water absorption. It may have the potential for use as a wound dressing in vivo.
Subject(s)
Biocompatible Materials/chemical synthesis , Collagen/chemistry , Occlusive Dressings , Polyvinyl Alcohol/chemistry , Biocompatible Materials/chemistry , HumansABSTRACT
We have prepared a wound dressing made from chitosan and collagen. Its clinical curative effect was detected. Chitosan solution was put into purified collagen solution. Then, the solution became sponge by means of freeze drying, and it was subjected to a series of toxicology tests, including acute toxicity, stimulation test, allergic and hemolysis tests, as well as the clinical test of openning trauma in orthopedics. All of the results of toxicology tests were negative. The chitosan-collagen sponge could not only accelerate the speed of curing but also restrain the extravasate. Therefore, the chitosan-collagen sponge has good biocompatibility and clinical curative effect. It is a prospective security-biomaterial for medical use.
