Abstract
Amino acid analysis is a classic biochemical technique which has been well characterized with pure protein samples. Much less is known about the effect of the presence other substances in hydrolyzed heterogeneous samples upon the final results. At the Molecular Structure Facility at UCDavis (MSF), we examined amino acid recovery following hydrolysis to determine if the presence of carbohydrates during hydrolysis influenced the recovery of the amino acids. The MSF works with a diverse sample set for different customers and have a keen interest if any of the many substances present in the sample can influence the final results. A typical sample is subjected to 6N HCl for 24hr at 110°C then brought back up in an acidic diluent to run on our dedicated Hitachi 8800 which utilizes ion-exchange chromatography with a post-column reaction with ninhydrin for quantification of each amino acid. We used this typical/routine hydrolysis in our experiments. One technique which is often employed to promote complete hydrolysis is to presoak the sample in dilute acid was also examined. Using various model proteins as well as varying percentages of carbohydrates we demonstrated that the presence of carbohydrates has little effect on the recovery of protein across a wide range of concentrations.