The HLD I-IV dataset is created by the EnzymeMiner tool . As an input sequence, 3.8.1.5 -Haloalkane dehalogenase was used, and from the sequence selection table, all 33 provided sequences together with their essential residues were selected. In advanced options, only the maximum number of hits in PSI-BLAST was changed to 50000. The resulting dataset was composed of 22567 sequences (job ID xvmwa7). For a given query sequence, the MSA was preprocessed through several steps: (i) the gap positions in the query were removed for every input sequence except for the columns where less than 20% of sequences had gaps; (ii) sequences with gaps in more than 40% of positions were removed; (iii) sequences were clustered by 90% identity to support the diversity, and only one sequence for each cluster was picked for the training dataset, together with the query sequence, (iv) sequences with less than 50% overlap with the query were excluded. The sequence P59336_S14 of DhaA (Haloalkane dehalogenase from Rhodococcus sp) was chosen as a query for the training process. This resulted in 12053 sequences with 299 positions in the MSA left for the training after the preprocessing.