The secreted proteins that are less Ac-YVAD-pNA abundant on D-maltose, on Dxylose or both of these conditions include enzymes such as RNases, amidases, ANAFP and a homologue of yeast Wsc1 protein, involved in cell wall maintenance. The reason why these secreted proteins are decreased upon D-maltose or Dxylose induction is unclear. Possibly, these proteins are not subject to regulation by carbon substrate, and their decreased abundance relative to the total proteins secreted is a consequence of increased production of the extracellular enzymes induced by D-xylose or Dmaltose. In one of our previous studies, the effect of induction by Dxylose on microsomal proteins of A. niger was investigated using the same experimental setup as was used in the current study. Here, we have studied the induction by D-maltose and made a comparison with the D-xylose induced conditions. For the comparison of the different microsomal proteins present in each condition, the same method as the one used for secretome analysis was followed, i.e. ranking of the differential relative abundance by a G-test. An extensive list of proteins was obtained, and only the proteins with a G-score larger than 10 are discussed, i.e., the top 25% of the significantly increased and the top 10% of the decreased proteins upon induction. The proteins overrepresented upon D-maltose or D-xylose induction are SQ109 summarized in Table 2. In total, 27 proteins were significantly more abundant upon D-maltose or D-xylose induction as compared to the D-sorbitol control. On D-xylose 26 proteins were more abundant and on D-maltose 37 proteins. The proteins that were more abundant on the D-maltose and D-xylose conditions compared to D-sorbitol were identified as ERAD or mitochondrial proteins. In previous work we have shown that the proteasome 20S core particle is associated with the microsomal fractions by recruitment upon D-xylose induction, but this does not occur upon D-sorbitol addition. Here we find identical results upon induction with D-maltose. Other proteins that are highly expressed in both induction conditions include the ribosomal assembly protein, a small GTPase for vesicular transport, a plasma membrane ATPase for cell polarity and the metabolic enzyme oxaloacetate acetyl hydrolase involved in oxalate formation.