The present invention provides peptides for inhibiting various protein kinase C isozymes. The peptide can be directed to any region of the protein kinase C isozyme, and in one embodiment, is directed to the V5 domain. The peptide can be conjugated to a carrier, in a releasable or non-releasable manner. The peptides can be used to inhibit angiogenesis and/or vascular permeability. The peptides can be used to treat subjects having, for example, cancer, diabetic blindness, macular degeneration, rheumatoid arthritis, or psoriasis.