Literature says it can harm the enzymes is you step too fast. Because of this the standard is 1c/min raise.
No. I'm going to have to call BS on this one. I can only assume that the references recommend a 1C/min rate to avoid local overheating of the wort. If you have a bottom-fired or jacketed mash tun, then I'll agree that the rate is appropriate. If you run HERMS or RIMS, then the wort can go directly to the targeted step temperature with no detriment. Of course, this assumes that your HERMS or RIMS has proper process controls to avoid overheating the wort. The temperature sensor controlling the heating system must be immediately downstream of the heat source.
My 4500w RIMS wort circuit can step my wort directly to next temperature and I've never observed a problem with conversion or attenuation. However, I can point out that I DID have attenuation problems in my previous RIMS when I didn't have proper PID-control on the wort heating circuit. Created several 'worty' beers during that time. Overheating your wort will create the problems that the 1C/min recommendation is trying to help you avoid.
If you have the right equipment, the rate doesn't matter. Hit your target wort temperature and let the rest of the mash rise as the pulse of hot wort makes its way through the grist.