TY - JOUR PY - 2014// TI - Phenolphthalein false-positive reactions from legume root nodules JO - Journal of forensic sciences A1 - Petersen, Daniel A1 - Kovacs, Frank SP - 481 EP - 484 VL - 59 IS - 2 N2 - Presumptive tests for blood play a critical role in the examination of physical evidence and in the determination of subsequent analysis. The catalytic power of hemoglobin allows colorimetric reactions employing phenolphthalein (Kastle-Meyer test) to indicate "whether" blood is present. Consequently, DNA profiles extracted from phenolphthalein-positive stains are presumed to be from blood on the evidentiary item and can lead to the identification of "whose" blood is present. Crushed nodules from a variety of legumes yielded phenolphthalein false-positive reactions that were indistinguishable from true bloodstains both in color quality and in developmental time frame. Clothing and other materials stained by nodules also yielded phenolphthalein false-positive reactivity for several years after nodule exposure. Nodules from leguminous plants contain a protein (leghemoglobin) which is structurally and functionally similar to hemoglobin. Testing of purified leghemoglobin confirmed this protein as a source of phenolphthalein reactivity. A scenario is presented showing how the presence of leghemoglobin from nodule staining can mislead investigators.
Language: en
LA - en SN - 0022-1198 UR - http://dx.doi.org/10.1111/1556-4029.12352 ID - ref1 ER -