Inhibitory activity of purified SAP against P. porphyrae as determined by the disk diffusion susceptibility test. Disk 1, 100 μg of purified SAP/disk; disk 2, 50 μg/disk; disk 3, 25 μg/disk; disk 4, 12.5 μg/disk; disk 5, 6.3 μg/disk; disk 6, 3.2 μg/disk; disk 7, 1.6 μg/disk; disk 8, 0.8 μg/disk. The approximate MIC was determined to be 1.6 μg/disk.