Both parts belong to the same Implementing Rule 1321/2014. Part-145 regulates approved maintenance organisations while Part-M and Part-ML respectively, describe the maintenance processes.

Article 2 of 1321/2014 reads:
(h) ‘maintenance’ means any one or combination of the following activities: overhaul, repair, inspection, replacement, modification or defect rectification of an aircraft or component, with the exception of pre-flight inspection;

(j) ‘pre-flight inspection’ means the inspection carried out before flight to ensure that the aircraft is fit for the intended flight;

M.A.201 (d)
The pilot-in-command or, in the case of aircraft used by air carriers licensed in accordance with Regulation (EC) No 1008/2008, the operator, shall be responsible for the satisfactory accomplishment of the pre-flight inspection. That inspection shall be carried out by the pilot or another qualified person and shall not need to be carried out by an approved maintenance organisation or by certifying staff.

ML.A.201 (d)
(d) The pilot-in-command of the aircraft shall be responsible for the satisfactory accomplishment of the pre-flight inspection. That inspection shall be carried out by the pilot or another qualified person but need not be carried out by an approved maintenance organisation or by certifying staff.

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