gentamycin C1 CHEBI:24209 CHEBI:5309 chebi_ontology Gentamicin C1 O-2-amino-2,3,4,6,7-pentadeoxy-6-(methylamino)-alpha-D-ribo-heptopyranosyl-(1-4)-O-(3-deoxy-4-C-methyl-3-(methylamino)-beta-L-arabinopyranosyl-(1-6))-2-deoxy-D-streptamine CHEBI:27412 gentamycin C