This dataset contains a binary classification problem. Each row represents a protein binding site which class is given by the leading integer '-1' or '+1', respectively. After ':' the histogram-valued attributes are followed, where each bin is separated by a ',' and where the histograms are separated by a ';'.

The entries are absolute frequencies; thus, to produce a relative frequency distribution, they still need to be normalized. The frequencies are separated by a comma and the histograms by a semicolon. The histograms are arranged as follows:

Histogram  1: "Acceptor" -- "Acceptor"
Histogram  2: "Acceptor" -- "Donor-Acceptor"
Histogram  3: "Acceptor" -- "Donor"
Histogram  4: "Acceptor" -- "Aliphatic"
Histogram  5: "Acceptor" -- "Aromatic"
Histogram  6: "Acceptor" -- "Pi"
Histogram  7: "Acceptor" -- "Metal"
Histogram  8: "Donor-Acceptor" -- "Donor-Acceptor"
Histogram  9: "Donor-Acceptor" -- "Donor"
Histogram 10: "Donor-Acceptor" -- "Aliphatic"
Histogram 11: "Donor-Acceptor" -- "Aromatic"
Histogram 12: "Donor-Acceptor" -- "Pi"
Histogram 13: "Donor-Acceptor" -- "Metal"
Histogram 14: "Donor" -- "Donor"
Histogram 15: "Donor" -- "Aliphatic"
Histogram 16: "Donor" -- "Aromatic"
Histogram 17: "Donor" -- "Pi"
Histogram 18: "Donor" -- "Metal"
Histogram 19: "Aliphatic" -- "Aliphatic"
Histogram 20: "Aliphatic" -- "Aromatic"
Histogram 21: "Aliphatic" -- "Pi"
Histogram 22: "Aliphatic" -- "Metal"
Histogram 23: "Aromatic" -- "Aromatic"
Histogram 24: "Aromatic" -- "Pi"
Histogram 25: "Aromatic" -- "Metal"
Histogram 26: "Pi" -- "Pi"
Histogram 27: "Pi" -- "Metal"
Histogram 28: "Metal" -- "Metal"

Please note that the dataset contains an additional 29th histogram which is giving for each physicochemical property the number of occurrence. The ordering in this histogram is "Acceptor", "Donor-Acceptor", "Donor", "Aliphatic", "Aromatic", "Pi", "Metal".