Yes, you are eligible to apply for the Graduate Aptitude Test in Engineering after M.Sc. in Biochemistry, because according to the GATE eligibility “Master degree holders in any branch of Science / Mathematics / Computer Science / Statistics from a recognized University OR appearing in the final year of master degree course may also eligible to apply ”

GATE is jointly conducted by:
IISc Bangalore
IIT Bombay
IIT Delhi
IIT Guwahati
IIT Kanpur
IIT Kharagpur
IIT Madras
IIT Roorkee