Blood type (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cells. A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs).These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs).
Received July 13, 1990. DNA polymerase from Thermus aquaticus has be-. come a common reagent in molecular biology because of. its utility in DNA amplification and DNA sequencing. protocols. A simplified method is described here for iso-. lating the recombinant Taq enzyme after overproduc-. tion in Escherichia coli. Purification requires 8 to 10 h. and entails heat treating and clearing the E. coli lysate, followed by precipitation of the enzyme with polyethy-.
T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75â80 Â°C, with a half-life of greater than 2 hours at 92.5 Â°C, 40 minutes at 95 Â°C and 9 minutes at 97.5 Â°C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 Â°C.