The effect of blood inhibitors and enhancers on PCR, melting temperature, and polymerase activity. (A) DNA fragment of NP_001035158.1 gene (Fr. 7; 735 bp; 73.1% GC) was amplified in PCR mix II supplemented with the corresponding primers, 37.5 μM hemoglobin and 0.2 M trehalose alone (T), 1 M 1,2-propanediol alone (P) or their combination (PT). PCR mix supplemented with H2O instead of enhancers served as a control (C'). A typical experiment of four performed is shown. (B) Melting temperature of GC-rich dsDNA oligonucleotide primer No 7, reverse, and the anti-primer (72.2% GC; 1 μM final concentration) in the presence (+) or absence (-) of hemoglobin (37.5 μM) and various enhancers (as in A). Melting temperature was determined as in Figure 6, except that SGI was used at higher concentration (1.32 μM). (C) Enzymatic activity of Taq DNA polymerase in PCR mix II buffer supplemented with (+) or without (-) 10% blood and various enhancers (as in A). Samples supplemented with H2O instead of enhancers (C') served as controls. Data in B and C indicate means ± S.D. (n = 4). Asterisks indicate statistically significant differences (P < 0.05).