how do I put a variable into a b"" statement?

Question

so I want to put a variable into b'' , so I can do

# BYTEREAD.txt /format = utf-8
make \x52\x26\x2a\x40\x24\x26

# BYTE.py
with open('BYTEREAD.txt', r) as bt:
    print(b'{bt.read()}')

output from BYTE.py:
b'make R&*@$&'

I can't seem to find much on the internet so that's why I'm here