catalytic step 1 spliceosome
A spliceosomal complex that is formed by the displacement of the two snRNPs from the precatalytic spliceosome; three snRNPs including U5 remain associated with the mRNA. This complex, sometimes called the activated spliceosome, is the catalytically active form of the spliceosome, and includes many proteins in addition to those found in the associated snRNPs.
GO:0005681
spliceosomal complex
is_a
GO:1902494
catalytic complex
is_a
activated spliceosome
exact
mammalian spliceosomal complex B*
narrow
mammalian spliceosomal complex B2
narrow
yeast spliceosomal complex A1
narrow
SPAC29A4.08c SPBC19C2.01 SPAC3A12.11c SPCC550.02c SPAC9.13c