Editing the Pitch Map

Click on the little "Map" button at the center top of the screen to open the Pitch Map Editor.

image is 3/4 actual size

This is a set of 25 sliders that set MIDI Note values for each of the 20 Protein amino acids, plus the nonsense ("ZOT") codon; and the 4 DNA bases. These are labeled along the top. You can adjust the sliders to whever pitch you like within a 4 octave scale. As you move the sliders, they are labeled with the pitch value.

The row of small buttons under the sliders are quantization buttons, to force slider settings to the nearest value that will result in the scale given by the button label. The three larger buttons to the right will set a C Major, Kyte, and Chromatic scale.

Defalut Pitch Map and Kyte Scale

The default pitch assignments were made on the basis of the Kyte scale, which is a measure of the amino acid’s water-solubility of the amino acid. In general, hydrophobic amino acids are found in the interior of proteins and hydrophilic amino acids on the surface. The table below shows the pitches assigned to each amino acid. The default scale used is a pentatonic scale beginning with F sharp (F#). The numbers that follow the note names refer to the relative octave, i.e. Cn0 is an octave below Cn1. Lower pitches are given to the more hydrophobic amino acids, and higher pitches to more hydrophilic amino acids. Amino acids with similar solubilities have been clustered together. The four amino acids N, Q, D and E all have the same Kyte value, so they have been assigned the same pitch. In this table the amino acid number (AA#) is the order in which the amino acids are arranged on the Bio2Midi Pitch Table. The SL designation is the single-letter code used for each amino acid in genetics databases. For the four DNA nucleotides (A, G, C and T), the larger purine nucleotides have been given the pitches C#1 (G) and D#1 (A) and the two smaller pyrimidine nucleotides have been given the pitches F#1 (C ) and G#1 (T). The complementary nucleotides A /T and G/C are thus both a fourth apart on the scale. The pentatonic scale was selected because it has no obvious pitch center.

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