## 2 Database Description
The list of activities has been updated since 2019. The following activities have been recently added: membrane-active peptides, inhibitors of calpain 2 (EC 3.4.22.53), inhibitors of lipoxygenase, inhibitors of cyclooxygenase-1 (EC 1.14.99.1), inhibitors of cyclooxygenase-2 (EC 1.14.99.1), inhibitors of pancreatic lipase, inhibitors of angiotensin 2-converting enzyme (ACE2) (EC 3.4.17.23), inhibitors of acetylcholinesterase (AChE) (EC 3.1.1.7), inhibitors of butyrylcholinesteraseterase (BChE) (EC 3.1.1.8), and inhibitors of tyrosinase (EC 1.14.18.1). Among them, predicted ACE2 inhibitors and AChE inhibitors are represented in the BIOPEP-UWM Virtual database. The content of an exemplary peptide record from the BIOPEP-UWM Virtual database is presented in Figures 4 and 5. The peptide data record includes the following tabs (i.e., cards):  
* name (if possible) and sequence;
* function information--information about the predicted target biomacromolecule;  
Figure 5: Screenshot of the content from the tab “Screen and print peptide data” (see Figure 3): an exemplary peptide with BIOPEP-UWM Virtual ID: 151.  
bibliographic data with the reference paper describing the peptide;
* additional information, including the annotated peptide structure using chemical codes SMILES [17] and InChI [18], InChIKey identifier, specification of the method used for bioactivity prediction (to date, mainly molecular docking), information about other activities discovered experimentally or predicted using computational methods, and/or peptide taste (if available). The last category of content may include information about the main tastes (bitter, umami, sweet, sour, or salty) as well as enhancement or suppression of taste (e.g., bitterness-suppressing or umami-enhancing peptides). This information is taken from the BIOPEP-UWM database of sensory peptides and amino acids [15]. Information about the activity or taste of the peptide cites the database or databases providing this information;
* a database reference tab providing information about compound annotations in other databases (if available). The set of databases cited in this tab is described in our previous article [12]. Information about peptide annotation includes database name and compound ID. This tab also contains information about the annotation of peptides in the BIOPEP-UWM database of bioactive peptides and/or the BIOPEP-UWM database of sensory peptides and amino acids;
* entire peptide data arranged for printing, available via the \"Screen and print peptide data\". A table screenshot of the content of the above tab is shown in Figure 4.  
If the target biomolecule structure mentioned in the \"Function information\" tab is taken from a database, for example, the Protein Data Bank [19], an ID in the above database is provided. If the target molecule is a proteolytic enzyme, an accession number in the MEROPS database [20] is also provided. The \"Analysis\" tab includes all options available in the parent BIOPEP-UWM database of bioactive peptides [12]. It enables finding the location of all virtual bioactive fragments in a protein sequence; calculating quantitative parameters characterizing proteins as potential precursors of bioactive peptides; simulating enzymatic hydrolysis of proteins, followed by finding virtual bioactive fragments among predicted proteolysis products; using a batch processing option, enabling operations on a set of protein sequences without restrictions concerning the number or total length of sequences; converting amino acid sequences into SMILES representations; and finding enzymes potentially hydrolyzing given peptide bonds. Some changes concerning options available via the \"Analysis\" tab in all BIOPEP-UWM databases of peptides have been introduced since the publication of our previous article [12]. The first version of batch processing allowed processing a set of protein sequences with a total length of ca. 1500 amino acid residues [12]. This restriction was removed.