ⲅ is generally not used in genuine Egyptian words, because the Egyptian language (starting in Demotic, some centuries before Christ) did not differentiate between g and k. Everything was just ⲕ. Words which are written with the hieroglyphic sign for g usually show up as either ⲕ and ϫ in Bohairic, and ⲕ and ϭ in Sahidic, depending on the consonant environment.
ϫ in Bohairic stands for "dj" today (although many Copts pronounce it like g today because in Lower Egyptian Arabic dj turns to g - in Upper Egypt dj is still pronounced). But it stood for /c/ (in IPA, voiceless palatal stop) in earlier Bohairic. At least according to Carsten Peust "Egyptian Phonology", page 107.
ϭ in Sahidic stands for "ky", a palatalized k, while in Bohairic it stood for an aspirated voiceless palatal stop. Today, it is mostly just pronounced "tsh"