Name	Info	Provider	Link
mch	free resource	BioCyc	https://biocyc.org/gene?orgid=META&id=G-373
	subscription/membership/fee required	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/0014-5793(90)81477-6
	free resource	Wiley	https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0014-5793&date=1990&volume=275&issue=1-2&spage=226