instruction:
In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.
question:
 gp170 is expressed at a level 30 to 50 % of the Env precursor gp130 .
answer:
Env precursor


question:
 We have thus cloned two yeast homologs of mammalian p220 .
answer:
mammalian p220


question:
 Our data define Ile ( 16 ) , Val ( 18 ) , Val ( 31 ) , and Ile ( 33 ) as crucial for protein S binding , with secondary effects from Leu ( 38 ) and Val ( 39 ) .
answer:

protein S