Angle-Resolved X-ray Photoelectron Spectroscopy (ARXPS) was used to examine amino acid bonding and oxide removal on InAs(100) surfaces. Five amino acids were studied, including cysteine, lysine, aspartic acid, glutamic acid and arginine. Observations on the ability of specific functional groups to prevent oxide formation were made by examining the thickness of oxide films on the functionalize surfaces. Amino acids that possessed more than one functional group having resonance were shown to most effectively affect oxide formation. The influence of these groups on the electronic structure of InAs(100) provides insight into how multifunctional passivation strategies could be beneficial, as well as showing how biological molecules might affect detection when InAs(100) is used as a platform.