computePI               package:seqinr               R Documentation

_T_o _C_o_m_p_u_t_e _t_h_e _T_h_e_o_r_e_t_i_c_a_l _I_s_o_e_l_e_c_t_r_i_c _P_o_i_n_t

_D_e_s_c_r_i_p_t_i_o_n:

     This function calculates the theoretical isoelectric point of a
     protein. Isoelectric point is the pH at which the protein has a
     neutral charge. These estimate does not account for the
     post-translational modifications.

_U_s_a_g_e:

     computePI(seq)

_A_r_g_u_m_e_n_t_s:

     seq: AA sequence as a vector of chars 

_V_a_l_u_e:

     It returns the pI.

_N_o_t_e:

     Protein pI is calculated using pK values of amino acids described
     in  Bjellqvist et al. See also 'SEQINR.UTIL' for more details.

_A_u_t_h_o_r(_s):

     D. Charif

_R_e_f_e_r_e_n_c_e_s:

     The algorithm is quite the same as the one which is implemented at
     the following url:   <URL:
     http://www.expasy.org/tools/pi_tool-doc.html> 'citation("seqinr")'

_S_e_e _A_l_s_o:

     'SEQINR.UTIL'

_E_x_a_m_p_l_e_s:

     ss = read.fasta(File=system.file("sequences/seqAA.fasta",package = "seqinr"),seqtype="AA")
     computePI(ss[[1]]) 

