Neurotrophic protein; induces extensive neuronal differentiation in retinoblastoma cells. Potent inhibitor of angiogenesis. As it does not undergo the S (stressed) to R (relaxed) conformational transition characteristic of active serpins, it exhibits no serine protease inhibitory activity. {ECO:0000269|PubMed:7592790, ECO:0000269|PubMed:8226833}. This is the function of SERPINF1 (serpin family F member 1, Ensembl gene identifier ENSG00000132386).