Snippets

Dénes Türei Unknown headgroup mass calculation (PTPN9)

Created by Dénes Türei
unknown_headgroup.py
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#!/usr/bin/python2

from ltp import ltp2

ptpn9 = \
    [
        [338.143, 292.1328],           # ??
        [492.354, 255.2299],           # 16:0
        [518.370, 281.2452],           # 18:1
        [520.385, 283.2607],           # 18:0
        [730.584, 255.2298, 283.2610], # 16:0, 18:0
        [756.600, 281.2451, 255.2298], # 18:1, 16:0
        [756.600, 253.2142, 283.2604], # 16:1, 18:0
        [758.615, 283.2610, 255.2298], # 18:0, 16:0
        [784.622, 281.2452, 283.2607], # 18:1, 18:0
        [804.570, 281.2465, 255.2309]  # control: PC(18:1/16:0),
                                       # returns gly+P+choline (223.09734506418)
                                       # assuming formiate adduct
    ]

def get_headgroup_mass(m, ads = ['h', 'fo']):
    """
    Returns residual mass after calculating exact mass
    and removing fatty acid masses.
    
    :param list ads: Adducts assumed.
    """
    return \
        list(
            map(
            lambda ad:
                (
                    ad,
                    getattr(ltp2.Mz(m[0]), 'remove_%s' % ad)() - sum(m[1:]),
                ),
                ads
            )
        )

headgroups = \
    list(
        map(
            get_headgroup_mass,
            ptpn9
        )
    )

# resulted:
#[
    #[('h', 45.00292353322999),   ('fo', 1.0119971474307476)], # this does not make sense
    
    #[('h', 236.11682353323),     ('fo', 192.12589714743075)], # for 492.4, 518.4, 520.4:
    #[('h', 236.11752353322998),  ('fo', 192.12659714743074)], # headgroup has a mass
    #[('h', 236.11702353323),     ('fo', 192.12609714743076)], # either 236 or 192
    
    #[('h', 191.0859235332299),   ('fo', 147.09499714743072)], # 730.6 apparently does not
                                                               # fit in these series
    
    #[('h', 219.11782353323008),  ('fo', 175.1268971474309)],  # for 756.6, 758.6, 784.6:
    #[('h', 219.11812353323),     ('fo', 175.12719714743082)], # headgroup has a mass
    #[('h', 219.11692353322996),  ('fo', 175.12599714743078)], # either 219 or 175
    #[('h', 219.10882353322995),  ('fo', 175.11789714743077)],
    #[('h', 267.08532353323005),  ('fo', 223.09439714743087)]  # control, gly+P+choline mass correct
#]

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