The absorption of protein solutions in the UV is the result of tryptophan and tyrosine (and to a very minor, and negligible, extent phenylalanine and cysteine). The absorption maximum will depend on the pH of the solution, and spectrophotometric measurements are usually made in alkaline solutions. Absorption curves for tryptophan and tyrosine show that at …
There are three general methods to hydrolyze protein into its composition, amino acids. Those methods are acid hydrolysis, alkaline hydrolysis, and enzymatic hydrolysis. Strong acid is ordinarily the method of choice, and constant boiling hydrochloric acid, 6 M, is most frequently used. The reaction is usually carried out in evacuated sealed tubes or under N2 …
Measuring the purity of mRNA can be done by measuring its absorbance at 260 nm. An absorbance of 1.0at 260 nm is equivalent is equivalent to 40 mg mRNA. An additional reading at 280 nm allows the A260:A280 ratio to be calculated. A ratio of 2.0 should be expected. The integrity of the mRNA can …
How to make RNA get linear and prevent its secondary structure? In order to linearize or denature RNA, it can be achieved by heating to 80-90o for 5 minutes, then cooling quickly on ice (taking care not to cause precipitation of the loading-buffer components) and immediately applying it. The step above can reduce the RNA …
Taq polymerase is a thermostable DNA-dependent DNA polymerase that catalyzes the template-directed polymerization of dNTPs at high temperatures. Taq Polymerase was first isolated in 1976 from Thermus aquaticus strain YT-1. The Properties of Taq Polymerase Enzyme Taq Polymerase catalyzes the DNA-dependent polymerization of dNTPs, one unit of the enzyme is defined as the amount of …
RNA Polymerase is an enzyme that catalyzes the synthesis of RNA from ribonucleoside triphosphates in the presence of a DNA template and divalent cation, such as Mg2+ or Mn2+. The RNA molecules are synthesized complementary and antiparalel to one of the DNA strands in a 5, to 3, direction. The ribonucleotides are covalently joined together …
Restriction enzymes are endonucleases that recognize specific double stranded DNA sequences and cleaves the DNA in both strands. Restriction enzymes used in cloning are site specific. Cloning involves cleaving both the vector and genomic DNAs with a restriction endonuclease which yields compatible sticky ends, and then using those cohesive ends to recombine the DNAs into …