Alcohol oxidase of the methylotrophic yeasts: new findings

The paper summarizes some of our recent findings in structure–function organization of the alcohol oxidase (AO) from two species of methylotrophic yeasts. As revealed by PAGE, in methanol-grown Hansenula polymorpha DL1 and Pichia methanolica MH4 along with AO, the non-flavin minor protein having AO activity and different type of subunits is expressed. HLPC analysis of the content of FAD and its modified analogue (mFAD) in the AO isoforms of P. methanolica MH4 and the occurrence of mFAD in AO-lacking mutants of H. polymorpha DL1 imply a biosynthetic origin of this cofactor. Restricted degradation of the flavin part of mFAD by sodium periodate has established the presence of xylitol instead of arabitol. Thus, mFAD having such a xylose fragment is a xylo-FAD, but not arabino-FAD as reported earlier.