Compare the configuration in QI3/30002:
You can not save a material in MM02 without maintaining ANP code in QI3/30004 because the ANP code is configured as mandatory there.
Please refer to F1 help documentation for more detail.
Unlike configuration in WebClient UI, the property control in MM GUI is based on TRANSACTION DATA level, that is to say, different industry sector / different plant / different material type can have different field properties.
The field property maintenance is done in tcode OMSR:
The property is controlled by the calculation result based on combination of field references listed below: