3507.90 - Other:

This HTS category, 3507.90, encompasses a broad range of enzymes that are not specifically classified elsewhere within heading 3507. It covers prepared enzymes used for various industrial, diagnostic, or research purposes, excluding those with more precise subheadings. The key characteristic for classification under this heading is that the substance functions as an enzyme, meaning it catalyzes specific biochemical reactions.

Distinguishing this category from its sibling, 3507.10.00.00 (Rennet and concentrates thereof), is crucial. While rennet is a specific enzyme primarily used in cheesemaking, 3507.90 covers all other enzymes. This includes a wide array of enzymatic preparations used in sectors such as food processing (e.g., amylases, proteases, lipases for baking, brewing, and tenderizing), textile manufacturing, detergent formulations, and biotechnology.

Within 3507.90, further subdivision is provided by subcategories. The most notable is 3507.90.20.00, which specifically enumerates Pencillin G amidase, an enzyme utilized in the pharmaceutical industry for antibiotic production. The remaining products fall under 3507.90.70.00, labeled as "Other." This residual category is for any enzyme preparation not otherwise specified, reinforcing the comprehensive nature of heading 3507.90 for enzymes not fitting into more granular classifications.