30405
[ 3H ] S - desoxy - BTX - B2 ( cysteine brevetoxin B ) was semi - synthesized from BTX - B by conjugation of cysteine at the C50 olefinic group , then [ 3H ] radiolabeled by C42 aldehyde reduction .
 [ 3H ] S - desoxy - BTX - B2, cysteine brevetoxin B, BTX - B, cysteine, olefinic, [ 3H ], aldehyde
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 [ 3H ] S - desoxy - BTX - B2, cysteine brevetoxin B, BTX - B, cysteine, olefinic, [ 3H ], aldehyde