What condition typically indicates protein contamination in nucleic acid samples?

The condition that typically indicates protein contamination in nucleic acid samples is when the OD260/OD280 ratio is less than 1.6. This ratio is used to assess the purity of nucleic acids. The absorbance at 260 nm relates to nucleic acids, while the absorbance at 280 nm relates to proteins.

A ratio of approximately 1.8 is generally considered to indicate pure DNA, while a ratio around 2.0 may suggest the presence of RNA. When the ratio falls below 1.6, it indicates that there are likely proteins or phenolic compounds present in the sample, as they absorb strongly at 280 nm, thus affecting the calculated ratio negatively.

This understanding of nucleic acid purity and the significance of the OD260/OD280 values is crucial for molecular diagnostics, as contamination can lead to inaccurate results in downstream applications such as PCR or sequencing.