Azed 1765 + Mephisto 2378

[elderly]

1A - Before dance, I note dons getting squiffy in Kingston duty-free. (two words, 6 + 4 letters) ?N???? SHOP
34A - Mac is programmed to accept "Big Beef" hi-fi sound system. (one word, 10 letters) ?M?I?NN??S
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12D - Directors rambling unpenned this caught on tape? (one word 12 letters. sorry no letters yet) ????????????
34A - Seeking mostly very little protein in nerve cells. (one word 10 letters) ???T?N???N
Thanks in advance

[Argee]

34 across could be Ambisonics.

Anagram of mac is with bison "Big Beef" in the middle?

[Argee]

1 across Inbond shop.

[mahonia]

34a is huntingtin

[crofter]

mahonia I've been coming back to this one time and time again with no success - but you're quite correct! This is the gene that causes Huntington's disease.

It's formed from Hunting + tin(y) = mostly very small!

Nice one!