A motif that is a featured pattern is discovered from the frequent patterns in amino acid sequences. To extract frequent patterns at high speed, a parallel Modified PrefixSpan with a master-worker paradigm was proposed. However, a master-worker paradigm has a performance limitation when the number of PCs increases. To address this disadvantage, the distributed worker paradigm is adapted to the parallel Modified PrefixSpan. In order to obtain an effective speed-up ratio, we propose a new dynamic load balancing. The characteristics of dynamic load balancing are a smallgrain task and a Cache-based Random Steal schema. When a 100-scale PC cluster was used, the experimental results showed a speed-up ratio of 95 times.