import re
pattern = re.compile( r'^((?=.*,)[^,]+|\S+)[\s,]+(.*)' )
texts = [">Keratyna 5, egzon 2, Homo sapiens", ">101m_A mol:protein length:154  MYOGLOBIN"]
for text in texts:
	m = pattern.search(text)
	if m:
	    id, description = m.groups()
	    print(f"ID: '{id}', DESCRIPTION: '{description}'")