Anti-Alga PCNA Antibody - Western Blot. Western blot of Affinity Purified anti-Alga PCNA antibody shows detection of a predominant band at ~29 kD corresponding to PCNA (arrowhead lane 2). Peptide competition effectively eliminates specific band reactivity (lane 1). For peptide competition, the antibody was pre-incubated with 100 ug (excess) of the peptide for 2h at 37? C followed by overnight incubation at 4C with 100 ug (excess) of the peptide, followed by a brief centrifugation and then reaction with the membrane. Each lane contains a lysate from 105 cells from the marine dinoflagellate Prorocentrum minimum. Cells were separated by SDS-PAGE and transferred onto nitrocellulose using standard techniques. After blocking the membrane was probed with the primary antibody diluted to 1:2001000. Incubation was followed by washes and reaction with HRP Gt-a-Rabbit IgG [H&L] MX (LS-C60865). Detection was by ECL using a 30 sec exposure time. Other detection systems will yield similar results. Personal Communication. S. Lin, U. Conn.