Biopharming with transgenic goats — which therapeutic protein expressed in goat milk has been used to dissolve blood clots?

Introduction / Context:
Transgenic livestock have been engineered to express human therapeutic proteins in milk, enabling large-scale bioproduction. Goats, in particular, have produced several proteins of clinical interest through mammary gland–specific expression.

Given Data / Assumptions:

• Target activity: dissolving blood clots (thrombolysis).
• Milk as bioreactor via mammary-specific promoters.
• Therapeutic examples include tPA variants and antithrombin (though AT acts as an anticoagulant, not a clot-dissolver).

Concept / Approach:

Tissue-type plasminogen activator (tPA) converts plasminogen to plasmin, which degrades fibrin clots. Transgenic goats have expressed tPA variants in milk, demonstrating bioactivity after purification. This is distinct from α1-antitrypsin (an antiprotease) and casein (a native milk protein).

Step-by-Step Solution:

Verification / Alternative check:

Published reports document tPA variants produced in goat milk; separate programs produced antithrombin (ATryn) in goats for anticoagulation (not direct clot lysis).

Why Other Options Are Wrong:

(b) AAT treats emphysema due to AAT deficiency; not thrombolytic. (c) Casein is structural milk protein. (a) APP is unrelated. (e) hGH is anabolic, not thrombolytic.

Common Pitfalls:

Confusing anticoagulants (prevent clots) with thrombolytics (dissolve clots); mixing goat-produced AT with tPA function.

Final Answer:

A variant of human tissue-type plasminogen activator