Question

Which of this is not an isoenzyme of creatine kinase?

(a) LDH5 (MMMM)

(b) CK1 (BB)

(c) CK2 (MB)

(d) CK3 (MM)

This question was addressed to me during an interview for a job.

The origin of the question is Clinical Significance of Trypsinogen and Creatine Kinase in section Clinical Enzymology of Enzyme Technology

Answer 1

Right answer is (a) LDH5 (MMMM)

For explanation I would say: LDH5 (MMMM) is an isoenzyme of lactate dehydrogenase which is made of M-type polypeptide. CK1 (BB), CK2 (MB) and CK3 (MM) are isoenzymes of creatine kinase. CK1 (BB) is found in CSF, whereas CK2 (MB) and CK3 (MM) is found in plasma.