Increased levels of caspase activity are often observed in a number of disorders, such as myocardial infarction and Alzheimer disease. Therefore, finding caspase inhibitors is of clinical value for prevention or diminution of the symptoms of these disorders. To achieve this goal, several soil isolates of bacteria were screened for caspase-9 inhibition. The microorganisms were grown on appropriate media in order to obtain adequate biomasses which then subjected to methanol extraction. The inhibitory potentials of dried extracts on caspase-9 were assessed by measuring the enzymatic activity of the recombinant caspase-9 using LEHD-pNA as a substrate. Caspase-9 was produced in E. coli and purified to homogeneity with Ni-NTA affinity chromatography. Caspase-9 activity was assessed in the absence or presence of the extracts in 1M ammonium citrate. Methanol extract from one of the microorganisms was able to inhibit the activity in a dose dependent manner, potently. Five kDa cut off of the extract was also capable of exerting as potent inhibitory activity as the unfiltered sample, indicating that the inhibitor has a relatively small molecular weight. Small subunit ribosomal DNA technique is underway to identify the bacteria.
