NCJ Number
216811
Journal
Journal of Forensic Sciences Volume: 51 Issue: 6 Dated: November 2006 Pages: 1389-1396
Date Published
November 2006
Length
8 pages
Annotation
This paper describes a procedure that successfully identified the presence of saliva in a mixture of bodily fluids that contained alpha-amylase.
Abstract
The study found that the Amylase test, directly performed on a biological fluid or on a stain without any protein purification could be used as a quantitatively reliable, rapid, and low-cost kinetic method for distinguishing the presence of saliva from that of perspiration and urine and to identify the presence of saliva in mixtures with perspiration or urine. In the documented case in Italy, a mixture of bodily fluids was found on the underwear of a murdered female child. Short tandem repeat DNA typing determined that the mixture consisted of fluids from the victim (female) and the suspect (male). No seminal fluid was found in the mixture, so saliva from the suspect and urine from the child was hypothesized. Forensic scientists investigated the possibility of specifically and rapidly detecting saliva stains both alone and mixed with other bodily fluids. They used a quantitative spectrophotometric technique named Amylase test, which detects the alpha-amylases enzyme. In animals, alpha-amylases are monomeric, calcium-binding proteins that are produced and stored mainly in the salivary glands and in the pancreas and are abundantly present in their secretions. As alpha-amylases are secreted into the digestive system, small amounts enter the blood and are eliminated through urine and perspiration. The Amylase test in the documented case determined alpha-amylase activity and reaction kinetic curves in several samples collected from the child's underwear. The scientists first tested saliva, perspiration, and urine singularly and in mixtures; second, several forensic stains were tested. Evaluating alpha-amylase activity values and time-course curves' behavior of alpha-amylase reactions enabled the detection of saliva and its distinction from other fluids containing alpha-amylase. 5 figures and 32 references