Is a hormone, whereas is an enzyme.

Secretin is a hormone whereas pepsin is an enzyme. Secretin is a a hormone that is responsible for regulating homeostasis of water in the body and is released into the bloodstream. Pepsin is an enzyme which is responsible of breaking down proteins into smaller units.

Are there any options?

i see some aspects in common:
both oil and vanilla are relatively expensive and the countries can be sure to sell them. there isn't much competition (there is quite a lot of competition in oil, but the earth needs a lot of oil) and they can be sure that the prizes won't be suddenly lowered.

also, saudi arabia can barely export anything else, since it's mostly a desert.