diff --git a/challenges/pt-br/new-backend-challenge/discount.proto b/challenges/pt-br/new-backend-challenge/discount.proto
index 274f9fb..35ed49c 100644
--- a/challenges/pt-br/new-backend-challenge/discount.proto
+++ b/challenges/pt-br/new-backend-challenge/discount.proto
@@ -2,17 +2,18 @@ syntax = "proto3";
 
 package discount;
 
-// Service that return mocked discount percentage.
+// Service that return mocked discount percentage
 service Discount {
   rpc GetDiscount(GetDiscountRequest) returns (GetDiscountResponse) {}
 }
 
-// productID used to represent a product. Ilustrative only.
+// product_id used to represent a product. Ilustrative only.
 message GetDiscountRequest {
-  int32 productID = 1;
+  int32 product_id = 1;
 }
 
 // The discount percentage is a fixed value.
 message GetDiscountResponse {
   float percentage = 1;
 }
+