Abstract
The accuracy of initial guess is important factor to get the solution of Canonical Molecular Orbital （CMO）calculation for large molecules, such as proteins. Quasi-Canonical Localized Orbital （QCLO） method is one of the methods to make precise initial guess of a huge molecule. The previous QCLO program was developed based on peptide structure, so it was difficult to apply it to hetero molecules. Then, we have developed the new QCLO program, which can treat an arbitrary chemical structure, and made it possible to apply QCLO method to hetero molecules. In this study, using the new QCLO program, we analyzed the accuracy of its initial guess for Glucose Oxidase （GOX） model, which has a hetero molecule FAD as its active center. Electronic structure of the GOX active center, which is obtained by CMO calculation, was also studied.
