Business & farm

According to the IRS, it should be entered as "business interest" on Line 28.

See https://www.irs.gov/instructions/i1040se#idm140630719968528

However, the only apparent method to get that figure on that line in TurboTax Step-by-Step (the interview), is to enter the figure as partnership expenses (see screenshot below) in the K-1 entry section.

The entry will appear on Schedule E as "UPE" (unreimbursed partner expenses) which is probably not technically correct. You can override the description to read "business expenses" but TurboTax will flag that override and you could be forced to print and mail the return.