Insecticidal proteins exhibiting toxic activity against Coleopteran and Lepidopteran pest species are disclosed, and include, but are not limited to, TIC3668, TIC3669, TIC3670, TIC4076, TIC4078, TIC4260, TIC4346, TIC4826, TIC4861, TIC4862, TIC4863, and TIC-3668-type proteins. DNA molecules and constructs are provided which contain a polynucleotide sequence encoding one or more of the disclosed TIC3668-type proteins. Transgenic plants, plant cells, seed, and plant parts resistant to Lepidopteran and Coleopteran infestation are provided which contain polynucleotide sequences encoding the insecticidal proteins of the present invention. Methods for detecting the presence of the polynucleotides or the proteins of the present invention in a biological sample, and methods of controlling Coleopteran and Lepidopteran species pests using any of the TIC3668-type insecticidal proteins are also provided.