acyl-CoA (9+3)-desaturase activity
acyl-coa (9+3)-desaturase activity
Catalysis of the introduction of a cis double bond at position 12 of fatty-acyl-CoAs that contain a cis double bond at position 9. Specific reactions include: (9Z)-hexadecenoyl-CoA + 2 Fe(II)-[cytochrome b5] + 2 H+ + O2 = (9Z,12Z)-hexadecadienoyl-CoA + 2 Fe(III)-[cytochrome b5] + 2 H2O; and (9Z)-hexadecenoyl-CoA + 2 Fe(II)-[cytochrome b5] + O2 + 2 H(+) = (9Z,12Z)-hexadecadienoyl-CoA + 2 Fe(III)-[cytochrome b5] + 2 H2O.