negative regulation of protein sumoylation

uniprot-protein:A4GSN8, uniprot-protein:B5AFM5, uniprot-protein:B8AID9, uniprot-protein:B9F2X6, uniprot-protein:B9HI19, uniprot-protein:E2R8T7, uniprot-protein:E9Q2W1, uniprot-protein:F6RX57, uniprot-protein:F6TMZ0, uniprot-protein:F7AVN4, uniprot-protein:G1KRC7, uniprot-protein:G1MBZ6, uniprot-protein:G1QWI5, uniprot-protein:G1TSG0, uniprot-protein:G3H0X3, uniprot-protein:G3TVX4, uniprot-protein:G3VZS1, uniprot-protein:G5BM28, uniprot-protein:G7MWY9, uniprot-protein:H0XKK2, uniprot-protein:O13826, uniprot-protein:P16259, uniprot-protein:P20807, uniprot-protein:P43368, uniprot-protein:P51186, uniprot-protein:P87176, uniprot-protein:Q3U1L0, uniprot-protein:Q3U1Z7, uniprot-protein:Q64691, uniprot-protein:Q6Z7R9, uniprot-protein:Q6Z7S0, uniprot-protein:Q92177, uniprot-protein:Q9GLG7, uniprot-protein:Q9TTH8, uniprot-protein:Q9UT72, uniprot-protein:Q9Z104