Supermassive black holes (SMBHs) are believed to reside in the center of nearly every galaxy.  The primary characteristic of these SMBHs is their mass. However, only a few tens of SMBHs have had their masses determined since the observational methods for such measurements are limited.  One of these methods is reverberation mapping which can be applied to Type 1 Active Galactic Nuclei (AGNs).  Using reverberation mapping the SMBH mass in about 45 AGNs was measured in the past 25 years. However, all these AGNs have moderately high mass (10^6-10^8 solar masses) and luminosity (10^42 to 10^46 erg/s). To gain a better understanding of SMBHs there is an essential need to study the lowest and highest mass BHs that reside in AGNs. This talk will present our results from a study to measure the lowest mass AGNs using the reverberation mapping technique with the Hobby-Eberly Telescope.